5

Blossom Rock is one of the earliest-named features found in San Francisco Bay. Located approximately 5,500 feet southeast of Alcatraz Island, and 8,300 feet west of Treasure Island, the rock was named in 1826 by Captain Frederick W. Beechey of the Royal after his ship, HMS Blossom. Legend has it that Beechey named and charted the rock only after hitting it with his ship, but this could not be confirmed in the historical literature. Renowned 19^th century surveyor George Davidson described Blossom Rock in 1862 as “ . . . a ledge having five feet of water upon it at the lowest tides and . . . about 300 by 200 yards in extent[1]. . . .” (Davidson 1862:39). A painted spar buoy had been placed south of the ledge and Davidson advised that “vessels should not approach the buoy from any direction nearer than a cable’s length [720 feet] (Davidson 1862:39).

Its dangers to navigation were well known, as it was situated directly in the course vessels are often compelled to take in entering and leaving the harbor; was in the track of naval vessels passing to and from San Francisco and Mare Island navy-yard, and was also in the way of all passenger steamers and vessels plying between San Francisco and the Sacramento and San Joaquin Rivers (Williamson 1870:1).

In January, February, and March 1867, Lieutenant W.H. Heuer of the USACOE conducted test explosions on the rock “with gunpowder, with the view of estimating the cost of removal of the rock” (Heuer 1867:7). During the test period, Heuer detonated eight charges in sizes of 75, 125, and 175 pounds. Each charge was placed in a watertight cask, and inserted into a sack of sailcloth, which was then tarred. Two heavy pieces of iron were tied to the sides of the cask to hold it on the rock’s surface.

Soundings were then made to enable us to find the advantageous positions for the charge; a small scow was securely anchored over the spot; charge lowered into place; scow hauled about 200 feet away; . . . and the charge immediately exploded; the scow was then hauled back to its first position, and soundings were made, by which we ascertained approximately the effects of the blast (Heuer1867:8).

Based on the data collected by Heuer, an allotment of $50,000 for the removal of Blossom Rock was made the following year from the general appropriation for the improvement of rivers and harbors.

On November 20, 1868, Colonel R. S. Williamson of the USACOE San Francisco office received a proposal from a civilian engineer, Alexis W. Von Schmidt (Figure 2) to remove the rock to a depth of 24 feet at mean low tide. Von Schmidt[2], who had earlier blast-excavated the drydock at Hunters Point for banker William C. Ralston, proposed using a similar approach in removing Blossom Rock (Hittell 1882:431). For the sum of $75,000, Von Schmidt proposed excavating a number of chambers within the rock, placing charges within the chambers, then blasting “the crust over the chambers and drop the same to the bottom of the excavation”[3] (Von Schmidt 1868:19).

After soliciting proposals in several prominent newspapers, and receiving only one other bid in response, the USACOE accepted Von Schmidt’s proposal. An additional $30,000 was authorized for the work and a contract was made with Von Schmidt on June 16, 1869.

In October 1869, Von Schmidt commenced operations. He built a crib-work of timber that was launched and floated to the rock in November. The 32 foot-square structure featured a 10 foot-square cofferdam in its center (Figure 3). The outer edge of the crib was boarded up to a height of six feet, forming a box around the cofferdam that was filled with ballast stone, causing the crib-work to sink to the upper surface of the rock. Anchors were deployed and steel-pointed piles attached to the sides of the crib-work were driven into the rock. A floor was built across the top of the crib-work at a height 20 feet above the surface of the rock. On it, Von Schmidt built a shed that accommodated 15 men, who slept and ate on the structure during the course of the project.

Cement and sand were used to seal the interface between the surface of the rock and the bottom of the cofferdam, after which the cofferdam was pumped dry. Through the center of the cofferdam, Von Schmidt placed a 6 foot-diameter iron cylinder, 14 feet in height that rested on the dry surface of the rock. More cement and sand was placed in the cofferdam, between the interior surface of the cofferdam wall and the exterior surface of the cylinder, forming a watertight seal. Residual water was pumped from the cylinder and excavation commenced on December 7^th. Space within the cylinder was limited and only one person at a time could work within it. Using picks, gads, and sledgehammers, miners excavated a bore 10 feet into the surface of the rock, manually hoisting the excavated spoils up through the cylinder. At a depth of ten feet, a second iron cylinder of slightly smaller diameter was telescoped into the first, and later a third cylinder was telescoped inside of the second, extending the depth of the excavation to 14 ½ feet below the upper surface of the rock. From within the third cylinder, excavation continued until January 1870, when the shaft reached a point 30 feet below low water. From there, horizontal shafts, or “drifts” were excavated in the direction of the longer and shorter axes of the rock. A swinging derrick was built on the upper surface of the crib-work and steam power was used to hoist the tubs of excavated spoils to the surface (Figure 4). These were dumped over the side along the deeper slope of the rock and the tides carried much of the debris away.

With the excavation of the drifts, up to eight miners were able to work inside of the rock and by February, enough rock had been excavated from the interior that this number was increased to 16. The drifts were enlarged and connected and the interior of the rock began to resemble a large chamber, having an arched roof and supported by a dozen columns of rock. On April 20, 1870, excavations ceased. The chamber had increased in size, obtaining a height of 12 feet and lateral dimensions of 140 x 60 feet. With the exception of four columns near the shaft, all the rock columns had been removed and replaced with 8 x 10-inch wood timbers (Figure5).

Thirty-eight ale barrels, with an average capacity of 60 gallons each, and several old, riveted iron tanks were waterproofed with alsphaltum and filled with nitrate of soda powder. They were placed against the edges of the excavated chamber, about eight feet apart, and were linked together with iron gas pipe and rubber tubes, the terminal connection passing through the shaft and up through the cofferdam to the surface of the crib above (Figure 6). It was then publicly announced that on April 23^rd, the explosives would be detonated. On that day immense crowds gathered on Telegraph Hill and other prominent heights in the City to witness the removal of Blossom Rock. On the morning of the 23^rd, a 5 inch-diameter hole was cut into the iron cylinder, about two feet above the low water mark. As the tide rose, water flowed through the hole and slowly filled the chamber. By 2 p.m. a sufficient amount of water had filled the chamber and:

An insulated wire was connected with the one brought up through the hose (the other end of the wire being in the water) and a boat containing the Beardslee’s magneto-electric battery and the coil of insulated wire pushed off from the crib, paying out the wire as we proceeded. When about 800 feet from the crib the wire was cut and the end connected with one of the poles in the battery, the circuit being completed by a wire connected with the other pole dragging in the water. One turn of the battery-crank and the explosion instantly follows. A column of water, variously estimated at from 200 to 300 feet high, rose majestically in the air. The diameter of the body of water thus thrown up was probably 200 feet. Around the base of this column was another simultaneous outburst of water, probably 70 feet high, whose flood seemed to roll outward. High above the mass of water could be seen rocks and pieces of timber. The highest jet of water was that which came through the shaft, and appeared as black as ink (Williamson 1870:29-30). (Figure 7)

Soundings made after the blast indicated that the shallowest water over the rock was only 14 feet deep at mean low tide, 10 feet above the contracted depth of 24 feet. Initially, this relatively small shoal area was thought to be the location of the dump pile used during the excavations, as probes into its mass indicated it was composed of loose pieces of broken rock. When, after several days, it became clear that the tide was not going to carry off the mass of rubble, Von Schmidt was notified that he would have to take active steps to remove the debris. In response, he built a heavy, wrought iron rake, weighing 2 ½ tons (Figure 8). The rake was deployed through the center well of a scow that was pulled back and forth over the top of the rock by a steam-tug. As the rake was dragged over the rock, it scraped the debris from the top and pushed it into deeper water, increasing the depth of water over the rock by a few feet. Pieces of timber occasionally floated to the surface, leading to the conclusion that the lower part of the crib-work, filled with 200 tons of rock, must have fallen into the crater during the explosion. Charges of powder were then detonated in several places on the rock in an attempt to remove the vestiges of the crib that were projecting above the rock’s surface.

Measurements were again taken and it was found that the newly cleaned surface of the rock was uneven and that portions did not have 24 feet of water over them at low tide. Von Schmidt then resumed his work and on May 25, 1870 claimed to have achieved the required depth. Some controversy arose over the relative accuracy of the USACOE tide gauge used to make the measurements, and the gauge being used by Von Schmidt. The measurements differed by over a foot and it took considerable discussion between the parties to resolve the issue. Ultimately, Von Schmidt acknowledged that he was in error and began removing the 8 inches of rock that projected in spots above the 24 foot required depth. On December 6, 1870, he reported “So far as I am able to ascertain, I have 24 feet of water over the rock at mean low water” (Von Schmidt 1870:37). The following day, the USACOE met with Von Schmidt and together the parties took numerous soundings over the rock, each of which indicated 24 feet or more of water over the rock at mean low tide. On December 8, 1870, Von Schmidt’s work was accepted and the contract money was paid[1].

In summarizing the project, the USACOE determined that the excavation had not been deep enough to accommodate the mass of shattered rock that fell back into it. They suggested that had the excavation been 10 feet deeper, sufficient space would have existed to accommodate the mass of shattered rock that fell into the void after the blast, and still provide in excess of 24 feet of water above it. In addition, two other shortcomings were identified. The belief that the tides would carry away the excess debris proved to be fallacious; and since the chamber was only about two-thirds full of water at the time of the blast, it “made the resistance very much less than it would have been had the chamber, as well as the shaft, been filled . . .” (Williamson 1870:38-39). Nevertheless, Von Schmidt was highly praised in the report and today he is credited with developing the tunneling method of blasting submarine rocks (Hittell: 1882:431).

Within seven years of its removal, Blossom Rock was again developing into a menace to navigation. On Friday afternoon, January 26, 1877, while under tow from Vallejo by the tug Monarch, the ship Highland Light struck the rock. The ship drew 22 feet of water and was lightly loaded, so its momentum forced it over the rock. However, a second ship being towed by the Monarch, the Blanchard, drew 23 feet of water and grounded on the rock. It remained there for half-an hour, until the Monarch could pull her free. Speculation at the time suggested that dumping of mud in the Bay by the scows had contributed to the shoaling of the rock (Alta 1877:1).

In 1894, in the annual report to the Secretary of War, the Chief of Engineers of the USACOE included a report submitted by Col. G.H. Mendell on the preliminary examination of Blossom Rock. Mendell reported that minimum depth at mean low water was less than 23 feet, and that since 1870, when it had been determined to be 24 feet, one or more vessels had touched on it. Minimum depth at low water of spring tides was calculated at 21 feet or less. Given its large seagoing commerce, Mendell deemed the harbor to be worthy of an improvement that would increase the depth of water over the rock to 30 feet at mean low water (Mendell 1894a: 3256).

On June 13, 1902 Congress appropriated $50,000 for the removal of Blossom Rock to a depth of 30 feet. On November 26, 1902, a contract was entered into with Mr. Robert Wakefield, who agreed to do the work for $45,142.00. In May of the following year, Wakefield deployed a drilling scow over the rock but it appears the project did not begin smoothly:

A few holes were drilled, loaded, and fired. The scow was then removed, and at present [June 30, 1903] another small scow with a grappling tongs operated by steam on board is anchored over the rock, prospecting with a view to determine how much of the rock is broken. Blossom Rock has a volume of 4,630 cubic yards above the 30-foot plane of depth and the rate of rock removal required in the contract is at least 1,000 cubic yards per month. Work was required to be commenced on May 17 and completed on October 6, 1903. No rock worth mentioning has yet been removed (Annual Reports 1903:2184-85).

By December 28, 1903, Wakefield had completed the job and Blossom Rock had been reduced to a level 30 feet below mean low water (Hagwood 1982:72).

By 1928, the Chief of Engineers for the USACOE reported that ship traffic using the channel between Alcatraz Island and the San Francisco waterfront was subject to hazards, “particularly in foggy weather, on account of the presence of Alcatraz Shoal, Blossom Rock, and Rincon Reef Rock” (Jadwin 1928:3). To assure the safety of navigation, the San Francisco District engineer recommended the removal of the three shoals to a depth of 40 feet MLLW. Public hearings were held and unanimous support for the removal of Blossom Rock was received by the San Francisco Board of Supervisors, the Pacific American Steamship Association, the San Francisco Chamber of Commerce, the Down Town Association, and the United States Navy. Despite the request from some of these organizations that the rock be removed to depths of 45 to 50 feet, the USACOE entered into a contract to have it reduced to a depth of 40 feet. Work commenced on the project on December 10, 1931 and at its completion on August 31, 1932, Blossom Rock had been reduced to a level 42 feet below MLLW (Annual Reports 1933:1076).

Shag Rocks is located approximately 4,400 feet northwest of Alcatraz Island and 1,000 feet southeast of Harding Rock. Davidson described “Shag Rock” in 1862 as a low, white-topped rock, about half a mile nearly N.NE from Bird Rock [Arch Rock]. . . . The rock shows about four feet above the highest tides, being then not more than 8 or 10 feet in extent (Davidson 1862:39).

Some confusion exists in the historic literature regarding the name of this rock. In Beechey’s 1827-28 chart of San Francisco harbor, the rocks that presently bear the name Shag is simply labeled as “rock.” Southeast of Point Avisadero [Hunters Point], however, Beechey has identified “Shag Rock.” As late as 1891, this rock along the City’s southern shoreline was known by this name. It was, in fact, the subject of some controversy when it was offered for sale to the City as a site for a proposed smallpox hospital. It was owned at the time by none other than A.W. Von Schmidt, who offered to sell it and a surrounding parcel to the City for $15,000 (S.F. Reports 1892:18-25).

In 1888, Professor George Davidson published a report on the southern Shag Rock, which at the time he recommended as a site for a quarantine station. In his report, Davidson discussed the pros and cons of siting the station at various locations around the Bay, stating in one part

If it [the quarantine station] were placed on the northern part of the bay, say for instance at Sausalito, it would require the crossing of the bay to that place, with strong westerly winds, strong irregular currents, and in summer dense fogs and the dangers of Arch and Bird rocks (S.F. Reports 1903:18-20).

In view of his 1862 description of Shag Rock cited above, it is puzzling that he would not mention that were two rocks named Shag in the Bay. Since Arch Rock was also known as Bird Rock, Davidson’s reference in 1888 to Bird Rock may have been to the rock also known as Shag Rock #2, although this is not clear since, as cited below, he makes a statement that Arch and Bird rocks are the same.

In any event, the rock of concern is the Shag Rocks situated northwest of Alcatraz Island. It was once known as Barrel Rock and, along with its neighbor Arch Rock, was considered a menace to navigation (Hansen 1995:62; Hagwood 1982:69; S.F. Call, 1 May 1900). Shag Rocks, in fact, was apparently supposed to be blown up on the same day that Blossom Rock was removed “but owing to mishaps in perfecting plans, the work could not be accomplished until [April 30, 1900]” (S.F. Call, 1 May 1900).

Shag Rocks, so named because it was a favorite resting place for shags[2], was composed of nearly 4000 cubic feet of metamorphic sandstone (Inkersley 1900:43). As depicted in the 1886 navigation chart “Entrance to San Francisco Bay, California, ” the designation “Shag Rock” appears to have encompassed two distinct pinnacles (Figure 9).

On September 14, 1899, Rudolph Axman was awarded a contract valued at $253,500 to remove Shag Rocks 1 and 2, and Arch Rock, to depth of 30 below mean low water. Work commenced on December 3, 1899 (Hagwood 1982:69; Annual Report 1900:625). Two months were required to build the drilling derrick and to move the associated machinery in position to drill the required holes in the rock. Axman stepped a 24 inch by 68-foot timber mast on the rock, supporting it with four guy wires anchored in the bay. A wood platform, 25 feet wide and 140 feet long, was suspended from the top of the mast so that it hung about seven feet above the water. The various steam drills and associated equipment were staged on this platform. Quarters and eating facilities for the workers, and the boilers for the steam drills, were placed on a large scow anchored near the platform (Hagwood 1982:70; Annual Report 1900:625).

Axman detonated several surface charges of nitrogelatin on the rock, which resulted in about 30 yards of rock being removed. This approach quickly proved to be ineffective so in February 1900, drilling operations commenced. Drill bits measuring 3 ¾-inches in diameter were used to drill holes to below the 30-foot grade line. The rock was so soft, however, that the bits jammed and when they were withdrawn, the holes would refill with the soft rock material. Eventually, Axman resorted to using larger, 10-inch diameter drill bits and iron casings to line the boreholes. By April 24, 1900 nine 3 ¾ inch diameter holes and 24 10-inch diameter holes had been drilled to depths ranging from two to seven feet below the 30-foot grade plane. The larger diameter bores were cased above the high-water level and connected to each other by wooden beams to stabilize them in the high winds prevalent on the bay.

The ten inch bores were loaded with nine inch by 18-inch cylinders containing over 16,000 pounds of nitrogelatin. Four blasting caps, each containing about half-a-pound of fulminate of mercury, were placed around the mouth of each hole. Platinum rods connecting the positive and negative poles of a battery were placed in the fulminate. Because nitroglycerin does not ignite readily, each blasting cap was surrounded by dynamite. (Hagwood 1982:69; Inkersley 1900:43) (Figure 10)

After Axman disassembled the wood platform, two tugs, the Lottie and Transit, were used to tow a barge carrying the system’s operators away from the blast site. As it went, Axman payed out the insulated wire that was connected to the fuses. When they were about 6000 feet from the wood mast, he connected the wire to a battery. At 3:00 p.m. on April 30, 1900, one of the tugs sounded three sharp warning whistles and, after an interval of five minutes, full current was applied to the circuit. This raised the temperature of the platinum rods to a red heat and ignited the fulminate, which in turn exploded the dynamite, and set off the nitroglycerin. After a muffled, almost imperceptible shock, a shaft of water 500 feet in diameter rose 996 feet into the air in just under 9 seconds (Figure 11). Hundreds of rocks, one estimated to weigh 7,000 pounds, were thrown some 500 feet into the air (Inkersley 1900:43; Hagwood 1982:72). As with the removal of Blossom Rock thirty years earlier, thousands of witnesses thronged the shoreline from the Powell Street wharf to Black Point, and perched on the heights of Telegraph and Russian hills to view the sight (S.F. Call 1 May 1900).

Following the blast, Axman brought a dredge to the site and began removing the shattered rock, some of which was deposited in the deeper water adjacent to the remaining basal portion of Shag Rocks. Using a large clamshell dredge, and with a few more surface blasts of the rock’s remains, the required depth of 30 feet below mean low water was achieved on July 30, 1900. Attention then turned to the smaller protuberance of Shag Rock No. 2.

Unlike the reduction of Shag Rock No. 1, this smaller pinnacle was reduced by surface blasting alone. Before the project began, the crest of Shag Rock No. 2 was 17 feet below the low-tide level. To reduce the pinnacle to the required elevation of 30 feet below low mean water, bags of nitrogelatin were placed in haphazard fashion over the rock, held in place with bags of sand, and detonated with an electric battery. This process continued until April 5, 1901, by which time the rock had been reduced to the required elevation of 30 feet below low mean water (Annual Reports 1901:3411; Hagwood 1982:72). Confirmation of this depth was obtained by a means of a final survey, the method of which was novel enough to be documented and included in the Chief of Engineer’s Annual Report.

Having completed a portion of his contract, Axman was paid $30,000 for removing Shag Rocks and immediately began preparing to complete the remainder of the $253,500 project, which included removing Arch Rock and the shoal extending from Alcatraz toward Sausalito (S.F. Call 1 May 1900).

By 1928, the USACOE district engineer for the San Francisco district was reporting that in “view of the large and important commerce, the increased size of vessels, and particularly on account of the long periods of dense fogs which prevail in the harbor . . .” Shag Rocks Nos. 1 and 2 should be removed to a depth of 35 feet at mean lower low water (Jadwin 1928:5). Work on reducing Shag Rocks to this new depth commenced on December 10,

1931 and continued until August 31, 1932, when a controlling depth of 37 feet mean lower low water was achieved and the project was considered complete (Annual Reports 1932:1076)

The biggest of the five rocks in the study area, Arch Rock is located approximately 1,600 feet south of Shag Rocks and approximately 4,000 feet west of Alcatraz Island. Davidson describes this rock as follows:

Bird or Arch Rock is a small pyramidal rock about 45 feet in diameter, 3 feet high, and bearing . . . distant seven eights of a mile from the lighthouse on Alcatraz Island. When seen in the direction from or towards the Presidio Shoal, it presents a perforation at low tide.

Residents of Sausalito apparently objected to proposals that the rock be removed since, with its arch visible at low tides, it was one of the popular sights of the Bay. Bay pilots, however, considered it a menace to navigation and urged that it be removed. One of the pilots, Mr. Frank Boyd, is quoted as saying:

When they come to survey that spot they will find every inch of ground in the vicinity of Arch Rock covered with anchors and chains. Coasters and deep water ships by the hundreds have come within an ace of going on the rock and had to slip their anchors in order to get clear (S.F. Call: 19 September 1900).

Nonetheless, its charm seems to have belied its danger. In the mid-19^th century, a favorite amusement was to pull a boat through the arch at low tide. A popular bar pilot pulled a Whitehall boat through the arch in 1857 and in 1859, two other pilots pulled a yawl through the opening. A few years later, a couple of men tried duplicating the feat but a heavy swell coming through the Golden Gate crushed them against the top of the arch. Apparently, it was the last time the feat was attempted (S.F. Call: 19 September 1900).

As reported by the USACOE in October 1894, the visible portion of Arch Rock “stands full 30 feet above the water. The visible portion of it is about 50 feet long and from 10 to 20 feet in width. It is a conspicuous object, both from its size and whiteness” (Mendell 1894b:3254) (Figure 12).

The Rivers and Harbor Act of March 1899 provided that, along with Shag Rocks, Arch Rock be removed to a depth of 30 feet below. The stipulation for this work was included in the contract awarded to Rudolph Axman on September 14, 1899. With the completion of his work at Shag Rocks, Axman began working on Arch Rock on September 15, 1900. As described in the Report of the Chief Engineers for that fiscal year:

A platform resembling a wharf, whose deck is about 9 feet above high-tide level, is built on wooden piles. It surrounds and is fastened to the pinnacle of the rock, which is about 30 feet above low-tide level. . . . Steam drills are placed on this platform, and holes about 18 feet apart and 10 inches in diameter are drilled to a depth of about 5 feet below the level of the grade plane. The drills are operated by steam furnished from a boiler on a large scow, which is moored alongside the drilling platform (Heuer 1901:3412).

By August 14, 1901, 236 holes had been drilled in Arch Rock (Figure 13). On the following day, the holes having been filled with 41,535 pounds of nitrogelatin, the final blast was detonated and Arch Rock was shattered into pieces. Dredging to remove the broken rock began on October 1, 1901. Along with additional surface blasting, it continued “until April 30, 1903, when, after repeated surveys and sweeping over the rock, it was found that the required 30 feet of depth below the mean of the lower low waters had been obtained” (Annual Reports 1903:2184).

In the 1928 report filed by the USACOE district engineer regarding the need to remove Shag Rocks Nos.1 and 2, Arch Rock was also identified as a hazard needing further reduction to the 35-foot depth. It was included in the same contract issued to remove Shag Rocks and several others in the bay, and by August 19, 1932, it had been blasted and dredged to a depth of 35 feet below mean lower low water (Annual Reports 1932:1076).

Located approximately 6,500 feet north-northwest of Alcatraz Island and approximately 2,000 feet northwest of Shag Rocks, Harding Rock is probably a pinnacle of the same rock mass that forms Shag Rocks. It was discovered in 1917 during a wire drag survey conducted by the U.S. Coast and Geodetic Survey and consequently, it is not mentioned in Davidson’s discussion of the Bay rocks. For at least the nine years following its discovery, it was simply identified as an unnamed obstruction on navigation charts. When it was referred to at all on the U.S. Coast and Geodetic Survey charts, it was noted as the “29 foot shoal.” As late as April 1926, it was referred to as “29 foot Rocks” (Schulz 1926:13, 16). The earliest reference to “Harding Rock” that could be found was that made by the USACOE San Francisco District Engineer T. H. Jackson in his 1927 report to the Chief of Engineers, wherein he indicated that Harding Rock was “previously designated 29-foot shoal” (Jackson 1927:34).

Despite a thorough examination of the historic literature, the source of the name “Harding Rock” could not be determined. President Warren G. Harding died in San Francisco on August 2, 1923 and it is possible that, in the intervening three or four years, the rock was named in his honor, but this could not be established with any degree of certainty.

Harding Rock was included in the 1928 report filed by the USACOE district engineer that recommended the removal of Arch Rock, and Shag Rocks 1 and 2. As with those rocks, the report recommended that Harding Rock be removed to a depth of 35 feet. The removal of the rock was included in the same contract issued to remove Arch and Shag Rocks and several others in the bay, and by August 3, 1932, it had been blasted and dredged to a depth of 35 feet below mean lower low water (Annual Reports 1932:1076).

This unique underwater geological feature is located approximately 0.5 miles west of Shag Rocks and 1.5 miles east of the Golden Gate. Little is know of it in the historic record. Informally called "Unnamed Rock" in the past, the geologic feature is formed by a pair of steep, sharply pointed, parallel ridges oriented towards the northwest that stand about 30 feet above the surrounding seafloor. The western ridge is higher than the eastern ridge by about 4 feet and rises to an elevation of about –55 feet MLLW. In between the ridges is a trough that ranges in depth from 75 to 86 feet in depth. The composition of the ridges is unknown but they are possibly semi-consolidated sedimentary features or underwater sand dunes, prompting a suggestion that a more appropriate name would be “Golden Gate Mounds” (Sea Surveyor, Inc. 2001).

Although hundreds of shipwrecks have occurred in the greater San Francisco Bay over the past 150 years, only 12 were identified in the initial records and literature search as potentially having encountered one of the rocks in the four survey areas, or potentially having sunk in their vicinity.

Shipwreck provenience and dates of potential mishaps as discovered in the records examined in the literature search, as well as the history of the wrecks' ultimate disposition, have in many cases, proven to be unreliable. This is often due to the fact that many of these records were compiled from historic accounts that tend to focus on descriptions of the wrecking incidents, and pay less attention to precise locations. In addition, many of the secondary sources used in compiling the records fail to describe the long-term aftermath of the wrecking incident. Many reported wrecks were, in fact, subsequently refloated and repaired, otherwise salvaged, or dismantled. Consequently, the identification of specific wrecks, and the suggested location of wreck sites within the vicinity of the survey areas should not be considered as absolutes. Examples of this will be evident in the discussions of the individual shipwrecks found below. The following ships were identified in the initial research as potentially lying within the survey areas. They are discussed in the chronological order of their purported demise.

In 1832, while on her way to Mexico, the 322-ton East Indiaman Seringapatan sailed into San Francisco Bay for supplies. After remaining in port for a week or two, she attempted to leave the harbor and resume her voyage to the south. In so doing, she struck Blossom Rock and hung there until a change of tides floated her off. Being made of teakwood, she received no injury and she proceeded on her voyage (Davis 1929).

The CSI record for this wreck, also attributed to Marshall (1978), simply describes the vessel as a 200 ton brig that went ashore on Angel Island on December 16, 1849, and was a total loss. No other information about the nature of the wreck or the ultimate disposition of the vessel has been found.

In perhaps his most cryptic unattributed reference, Marshall (1978:78) records the wreck of the Thomas Burnett as occurring at “Alcatraz in 1850.” As with the New England, this apparently is the source of the record found in the California Shipwreck Inventory. No other information about the vessel or the purported wrecking incident could be located.

In an unattributed reference, Marshall (1978:78) records the wreck of the barque New England at Angel Island in the 1850s. This apparently is the source of the record found in the California Shipwreck Inventory (CSI). No other information about the vessel or the purported wrecking incident could be located.

In an unattributed reference, Marshall (1978: 79) records the pilot boat Sea Witch sinking at Arch Rock on January 6, 1853. No contemporary account of the incident could be found in local newspapers, nor were any other records located to substantiate the wreck. Additional information regarding the disposition of the wreck is still being sought. In the San Francisco Call of September 19, 1900, bay pilot Frank Boyd is quoted on the incident:

The first vessel that I remember being wrecked on Arch Rock was the pilot boat Sea Witch. That was in 1855 [two years later than the recorded date]. All the pilots had “boarded off” and the schooner was coming in in charge of the boat-keeper. There was a dense fog and the boat-keeper mistook Arch Rock for a sloop under sail and getting his course accordingly, made the mistake of his life. All hands were saved but the Sea Witch was a total loss.

The California Shipwreck Inventory record, based on an entry in Marshall (1978) lists the Leonore as grounding on Arch Rock in 1855. No other information is provided in the record, or in Marshall’s text. Although there is a considerable amount of information about a ship named the Leonor that was quite prominent in the early history of California and operated along the coast from 1836 through 1845, this is a different vessel. The Leonore was a whaling ship either owned by or under contract to Tubbs & Co. of San Francisco. It arrived in San Francisco on November 7, 1855 with a cargo of 460 barrels of whale oil for Tubbs and Co. and cleared for another whaling voyage on December 3, 1855. If the vessel struck Arch Rock, it must have been a minor incident, since no record of it could be found.

As the clipper ship Goddess was beating out of the Bay towards the Golden Gate on July 25, 1856, she drifted onto Blossom Rock, then just five feet below the surface of the water. She remained fast upon the rock for approximately two hours, when she slid off without sustaining any damage (S.F. Bulletin: 25 July 1856). Presumably, she resumed her voyage to Calcutta.

The clipper ship Flying Dragon of Boston arrived off the San Francisco Heads on January 29, 1862, 35 days from Newcastle, N.S.W, then the fastest run on record (Boyd 1900:3). Under the command of a pilot, the ship was brought inside the Heads at 6:00 p.m. where a squall from the southeast struck her. The ship was anchored immediately but before sufficient chain could be let out, she dragged her anchors and struck Arch Rock. The flood tide kept the ship hard up against the rock and with torrents of rain pouring down, there was three feet of water in the hold within 90 minutes. Guns were fired and signal lights lit, attracting the attention of the garrison on Alcatraz Island. Boatloads of soldiers arrived to assist in manning the pumps, but it was to no avail. The ship, laden with 1000 tons of coal, resisted the efforts of a tug to pull her off and continued to settle lower in the water. By 8:00 the following morning, she had slewed around to the east of the ledge, with Arch Rock over her stern and her bow pointing towards Alcatraz. Within thirty minutes, her bulwarks had disappeared below the water, and at 10 a.m., she rolled over on her starboard side (S.F. Bulletin 30 January 1862). Later that day, the ship, then declared a total loss, was sold to the firm of Fonda and Gray for $825. With a party of wreckers, the new owners set off for the ship on a tug boat to retrieve whatever articles they could bring ashore. As they were approaching the wreck, the vessel slipped off the rock and sank like a stone and “not a spar or a fragment has ever been recovered. Notwithstanding considerable effort was made to find the wreck, it has never been found” (Alta: 24 January 1867). The U.S. Coast Survey determined the wreck’s location in about 1865. Davidson describes the location as follows:

From it [the wreck site] the following bearings are given to determine its position: Shag Rock, N14ºE, distant 670 yards; Bird Rock, S88ºE, distant 330 yards. Bird Rock is on with the highest point of Yerba Buena Island from the wreck (Davidson 1862:39).

In 1953, as part of a promotion for its movie “City Beneath the Sea,” Universal Studios hired Podesta Divers of San Francisco to dive at Arch Rock in search of the Flying Dragon and the Autocrat, which reportedly sank there in 1868. No evidence of the wrecks was found and nothing was recovered except for a piece of rusty stove grating (Chronicle: 27 February 1953). Today the Flying Dragon it is recorded as lying in 120 feet of water, 270 yards east of Arch Rock (Marshal 1978:72)

On April 6, 1868, the Autocrat, a 1,130 tons burthen ship arrived in San Francisco, 153 days from Baltimore. At 9:00 p.m. that evening in a light westerly breeze, she drifted onto Arch Rock, striking heavily and turning broadside on the rock. A strong flood tide running at the time pinned her against the seaward side of the rock. Efforts to free her proved futile and by 11:00 a.m. the following day, she was stuck fast with eight feet of water in the hold and filling at the rate of four inches per hour. Later that day, the ship and her cargo, principally 1,450 tons of coal, were sold to T.J.L. Smiley for $10,500[3]. With ten feet of water already in the hold, Smiley quickly went to work with a large gang of men to dismantle the ship. Sails, masts, provisions, and a considerable amount of coal were recovered. By the following day, the ship was said to be “in a very easy position” and the salvage efforts were progressing smoothly. The sails were unbent, and the yards sent down; the cabin was stripped of all its contents and the wreckers had cut a hole in the ship’s port side to facilitate removal of the coal and a substantial quantity of provisions. It appeared that if the Autocrat could “be kept above water for twenty-four hours more, Smiley and Co. will be the possessors of all she is worth” (Alta: 9 April 1868). Despite the apparent success of the salvors, it is possible that the Autocrat was salvaged and repaired, as it remained enrolled in its homeport of Boston for another ten years, finally dropping off the enrollments in 1878 (Lloyds 1878).

On February 2, 1869, the U.S. Army’s steam screw McPherson collided with the Duke of Edinburgh while making her regular trip from Alcatraz and Angel islands to her berth at the Vallejo Street wharf. While engaged in conversation with other officers in the wheel house, Captain H.P. Toler, who was making his first trip in command of the vessel, failed to notice the proximity of the British ship Duke of Edinburgh, which was being towed to sea by the steam tug Goliah. When he discovered he was about to cross the bow of the ship, he ordered the engines reversed and the helm put hard over, but it was too late to prevent the catastrophe. The hawser between the tug and the ship caught the McPherson, carrying away the smokestack, pilot house, a large portion of the hurricane deck, and severely damaging the after-cabin. Quick thinking on the part of a crewman averted a complete disaster when he dashed below and opened the furnace doors and the steam valves, allowing the steam to escape, and preventing the boilers from exploding.

The pilot in charge of the Duke of Edinburgh immediately anchored the ship. Small boats were lowered and the 17 passengers and the crew of the damaged steamer were taken on board. Immediately after the accident, the Goliah towed the damaged steamer to the wharf, then returned to the Duke of Edinburgh to take off the injured and other passengers, bringing them to the Pacific Street wharf. Although seriously injured, Captain Toler recovered, as did a crewman who was thrown into the water, and the other four injured passengers. Two days following the collision, it was reported that Private Ernest Lacour of the Eighth U.S. Calvary, a passenger on the steamer, was probably drowned in the accident. When last seen, he was struggling in the water, and apparently went under the steamer’s bottom. Although it was presumed that all passengers had been rescued, Lacour had not been seen for two days and he was presumed lost (Alta: 2, 3, 4 February1869).

While enroute to the City from Sausalito on the evening of October 27, 1877, the ferryboat Petaluma encountered the steamer Clinton about halfway across the Bay. The Clinton, an old freight boat, had been employed in towing the barges of the North Pacific Coast Railroad. She was returning to Sausalito with no passengers and a crew of four. The Clinton had apparently been underway with no lights and was therefore not seen by the captain of the Petaluma until the two vessels were dangerously close to each other. The captain of the Petaluma sounded a whistle and put the helm hard over when he saw the Clinton, but the other vessel failed to respond. Before a second blast could be given, the Petaluma crashed into the Clinton, nearly cutting the old boat in two. The Clinton sank in a few minutes but the boats of the Petaluma succeeded in taking off all the crew, except for the engineer, who perished in the accident (Chronicle: 28 October 1877).

More details about the accident were made available the following day. The captain of the Clinton, the ironically named Charles Lucky, claimed that he saw the Petaluma approaching and gave the usual signal whistle for the Petaluma to take the port side but received no answer. He whistled again and put his helm hard over, but the Petaluma kept straight on her course. When the Petaluma finally signaled, it was too late to avoid a collision so Lucky put the helm over so as to take a glancing blow to lessen the shock. The Petaluma crashed into the Clinton amidships on the port side. Unbeknownst to Lucky, the mate and fireman jumped onto the Clinton when she struck. Following the collision, Lucky ran below decks to find his crew and encountered the engineer. While helping to search for the rest of the crew, the engineer fell into the breach made by the Petaluma. By the time Lucky found him, he was up to his waist in water and the ship was sinking fast. Lucky attempted to pull the engineer free but was unable to do so. With the hurricane deck sliding down upon him and the water rising above his waist, he made one last, desperate attempt to pull the engineer free, but it was no use. With his own life in danger, Lucky had to release his grip on the engineer and quickly make his way to the bow. The Petaluma was lying about 50 yards away. Lucky yelled for help, threw off his coat and boots, dived into the water and swam to the Petaluma, where he was pulled aboard with a rope. Once on board, Lucky confronted the captain of the steamer, who could not explain what happened, as he had been below when the collision accident. Lucky judged from this remark that a deck hand had been steering the boat prior to the collision.

A crewman from the Petaluma and the deckhand from the Clinton took one of the ships boats and rowed to the Clinton, whose smokestacks were still visible above the water, in an effort to locate the engineer. As stated, the Petaluma delivered her passengers to the City, then returned to Sausalito, leaving the ships boat to attempt a rescue of the Clinton’s engineer. The Clinton went down in about twenty fathoms of water and then “drifted along on the bottom to a point opposite Point Bonita” from where she was towed “to the flats off Saucelito [sic], where it is now anchored” (Chronicle: 29 October 1877)

The CSI record for this wreck, and its source (Marshall (1978) list the Seven Sisters as capsizing at Angel Island on August 21, 1892. In fact, the schooner capsized near the end of Mare Island on that date. Heavily laden with 29 tons of rock ballast and 181 cords of bark wood, the ship encountered a squall off Mare Island and quickly turned turtle. All hands were rescued except for the Captain, who drowned before rescue boats could arrive. The ship was towed to McNear’s Wharf where it was tied up (S.F. Examiner: 22 August 1892). The Seven Sisters was apparently refitted, as in 1902 it is registered in Seattle, WA (DOT1902:np). On September 1, 1905, she was stranded on Kotzebue Sound in Alaska where she apparently met her end, as she drops off the Seattle enrollment in 1906 (DOT 1906:np).

In summary, of the 12 possible shipwrecks identified in the initial records and literature as potentially having occurred within the survey areas, only two may actually have sunk within those boundaries, the Flying Dragon and the Autocrat. No information to either substantiate or refute the sinking of the Thomas H Benton, the Thomas Burnett, or the New England has been located. The Seringapatan, Leonore, Goddess, McPherson, Clinton, and Seven Sisters all either got off their groundings, did not sink, or were erroneously reported as having sunk. The disposition of the Sea Witch is still being investigated.

[1] A more accurate and sophisticated survey was conducted after the contract money had been paid. The USACOE took over 1800 soundings over the rock and determined that in seven places, there was less than 24 feet of water. Von Schmidt, at his own expense, hired a diver who scraped the seven small clumps of stone over the side. Subsequent re-survey determined that the entire rock had at least 24 feet of water over it.

[2] An American species of double-crested cormorants.

[3] The ship was valued at about $30,000 and the cargo at about $20,000.