number of spots, with least found depths of 20 to 22 feet (6.1 to 6.7 m.), rising abruptly from depths of 6 to 7 fathoms (11 to 12.8 m.). Another spot, known as Isaac Shoal, lies nearly 2 miles southeast by east from Rebecca Shoal and has a least depth of 14 feet (4.3 m.). The shoals are of the nature of coral heads, rising very abruptly from the deep water surrounding them, and there are probably other shoals not found by the survey. It is also probable that there are less depths than found by the survey on the charted shoals. Currents. In the channel between Half Moon Shoal and Rebecca Shoal slack water before the flood (northerly) occurs two hours after the time of low water at Key West, and slack water before the ebb (southerly) occurs two hours after the time of high water at Key West. The average velocity of the current at strength is threefourths knot. The times of slack water and the velocity of the current are considerably influenced by the winds.

Rebecca Shoal, a coral bank quite small in extent and with a least depth of 9 feet (2.7 m.) over it, lies about 7 miles westward of Half Moon Shoal.

Rebecca Shoal Lighthouse is a white dwelling on a brown pile foundation on the southerly edge of the shoal. The light is group flashing white (3 flashes every 15 seconds), 66 feet (20.1 m.) above the water, and visible 14 miles. A sector, in which the flashes are red, covers Isaac and Half Moon Shoals and The Quicksands.

So far as is now known the passage between Rebecca Shoal and Dry Tortugas is clear. The lower part of the passage, south of a line from Rebecca Shoal Lighthouse to Tortugas Harbor unused lighthouse and west of a line extending NNE. and SSW., and passing 1 mile west of Rebecca Shoal Lighthouse, has been examined with the wire drag. Included in the dragged area are the three 10-fathom (18.3 m.) spots on a line about 9 miles south of the northern limit of the drag work. Until more detailed surveys have been made of the remainder of this locality, vessels of the deepest draft should use this passage with great caution, as there are probably undiscovered spots with less depths than those now charted. A vessel is reported to have struck an obstruction 2 miles, 285° true (WNW. W. mag.) from Rebecca Shoal Lighthouse. No obstruction was found here with the drag set to a depth of 33 feet (10 m.) or over. A vessel is also reported to have struck an obstruction with about 18 feet over it 11 miles 147° true (SE. 7% S. mag.) from Rebecca Shoal Lighthouse.

Dry Tortugas is a group of small sandy reefs and keys about 10 miles long in a northeast and southwest direction and about 5 miles wide, lying 58 miles westward of Key West. Pulaski Shoal, the northeastern end of this group, is 12 miles northwestward of Rebecca Shoal and is marked by a whistling buoy. The keys are irregular in form, and in general rise abruptly from deep water, with fairly good channels between them. As the keys are low and generally barren of vegetation, with only seven of them showing above high water, they are not readily distinguished; but Fort Jefferson and Tortugas Harbor unused lighthouse on Garden Key, and Dry Tortugas Lighthouse, on Loggerhead Key, are good landmarks. On a clear day they may be seen at a distance of 10 or 12 miles, Garden Key having the appearance of a bare rocky island. Bird Key, a

small key lying three-fourths mile southwestward of Fort Jefferson, is a national bird reservation.

When approaching Dry Tortugas from eastward or southeastward, the lead is of little use to give warning of danger, as 10 to 15 fathoms is found close to the reefs in many places. Approaching from northwestward or southwestward, the water shoals more gradually; but in thick weather a depth of 10 fathoms (18.3 m.) is as close as any vessel should approach, unless sure of her position.

Tortugas Harbor unused lighthouse on Garden Key is a brown, hexagonal, pyramidal tower, 67 feet (20.4 m.) high.

Dry Tortugas Lighthouse on Loggerhead Key is a conical tower, lower half white, upper half black. The light is flashing white (light 1 second, eclipse 19 seconds), 151 feet (46 m.) above the water and visible 19 miles.

There are two buoyed channels known as Southeast and Southwest, which lead to the anchorages among the reefs, and on a clear day no difficulty need be experienced by a medium-draft vessel in entering, as the shoals are readily distinguishable by the difference in color of the water. All of the channels, except that part of Southwest Channel southward and westward of buoy No. 2, have been closely developed by survey with lead, but have not been dragged to develop the least depths. The bottom is so rocky and broken and the rocky heads are so small in extent that vessels should exercise the greatest caution, even in the buoyed channels, where the depths are not more than about 10 or 12 feet (3 or 3.6 m.) greater than the draft.

Southeast Channel leads between the reefs making off eastward from Long and Bush Keys and those making off westward from East, Middle, and Sand Keys. This channel has depths of 30 feet (9.1 m.) or more, but it should be used with caution by vessels drawing over 18 feet (5.5 m.).

Southwest Channel leads between the reefs making off southwestward and westward from Garden and Bird Keys and those extending south westward from Loggerhead Key. The least found depth on the usual course is 6 fathoms (11 m.), but it has not been closely developed outside of buoy No. 2.

Northwest Channel has been abandoned and the buoys have been discontinued.

There are numerous places among the reefs where vessels can anchor and find shelter from winds from different quarters, according to circumstances. The anchorage affording best shelter from all winds, although somewhat open to the northward, is northward and northwestward of Garden Key. It has good holding ground, and the depths range from 8 to 10 fathoms (14.6 to 18.3 m.). Excellent anchorage for small vessels and boats is found in the deep water known as Bird Key Harbor, close eastward of Bird Key, and also in what is known as Tortugas Harbor, the narrow channel leading to the wharf at Fort Jefferson through the reefs that surround Garden Key. Fort Jefferson has been abandoned, but the channel is well marked with beacons and buoys. These two anchorages are entered from northward and are used principally by the fishermen who frequent these waters.

Currents. In the Southwest Channel slack water before the flood (northerly) occurs about 20 minutes before the time of low water

at Key West, and slack water before the ebb (southerly) occurs about 20 minutes after the time of high water at Key West. The currents are nearly simultaneous in all the channels of these islands, and follow the general directions of them. The average velocity of the current between Loggerhead Key and White Shoal is 1.3 knots at strength. The velocities, as well as the times of slack water, are considerably influenced by the winds.

There are no regular pilots for Tortugas Harbor, but a competent fisherman or lighthouse keeper will usually come out and assist vessels to enter.

For 10 miles westward of Dry Tortugas the bottom is broken and irregular, and consists of coral rock with patches of sand and broken shell. The shoalest part of this area, known as Tortugas Bank, lies 7 miles west of Loggerhead Key, and has a least found depth of 38 feet (11.6 m.), but it has not been closely developed. Depths of less than 10 fathoms (18.3 m.) are found for a distance of 21/2 miles in all directions. Between Tortugas Bank and Dry Tortugas the depths range from 10 to 19 fathoms (18.3 to 34.7 m.). Tortugas Bank should be avoided by deep-draft vessels, especially during heavy weather.

KEY WEST TO SAN CARLOS BAY

From Cape Sable to San Carlos Bay the coast is low, sandy, and generally wooded, with few distinguishing features. Back of the coast is an extensive swampy region, practically uninhabited, known in the southern part as The Everglades. Off the coast the water is generally shoal, and the 10-fathom (18.3 m.) curve roughly approaches a line drawn north-northwestward from Key West to Tampa Bay Entrance. This part of the coast is seldom approached by deep-draft vessels.

Vessels of moderate draft, bound from Key West up the west coast of Florida, can lay a straight course from Northwest Channel to Sanibel Island Lighthouse, at the entrance to San Carlos Bay, a distance from Key West of 118 miles. This course lies well clear of all dangers, and the lighthouse on Sanibel Island is a good landfall during the day or night. However, on account of the frequency of northers during the winter months, this track is not recommended for small power boats, and the route across Florida Bay is to be preferred.

Calda Channel, leading northward from Man-of-War Harbor, Key West, is a narrow, crooked channel, good for a draft of about 5 feet (1.5 m.), and, although not marked, is easily followed by day. The northerly entrance may be found by following the edge of the bank, 5 miles northward of Key West, until a large wreck is in range with the square, concrete tower of the Havana-American Tobacco Co., bearing 151° true (SSE. 34 E. mag.).

Florida Bay, lying northward of Florida Keys, and between them and the south coast of the mainland of Florida, is a triangularshaped body of water extending in a general east and west direction. from Barnes Sound to Cape Sable. The depths are shallow and irregular, and the bottom is mostly coral, with a thin covering of silt in the eastern part. From April to October the waters of the

bay are clear and the shoals plainly discernible, but during the winter months the water is milky and the shoals indistinguishable.

In the eastern part of the bay there are numerous ridges and reefs, which show bare or nearly bare, and there is also a large number of small wooded keys. This part is navigable only for small craft, and is mostly frequented by small motor yachts, spongers, fishermen, and the inhabitants of the keys, who generally use flat-bottomed boats of 3 to 4 feet (0.9 to 1.2 m.) draft. The western part of the bay is comparatively clear, with depths ranging from 7 to 13 feet (2.1 to 4.0 m.), and the bottom is covered with loggerhead sponges and small coral heads.

Moser Channel, 39 miles eastward of Key West, affords a passage between the Florida Keys from Hawk Channel to Florida Bay, which is used by vessels of 6 to 7 feet (1.8 to 2.1 m.) draft, coming either from Key West or from the east coast of Florida, and bound to points on the west coast. By this route small craft find comparative shelter in the shallow waters of Florida Bay, and protected anchorages are at no great distance apart. Moser Channel is crossed at its southerly end by a drawbridge with an opening 106 feet wide on each side of the central pier.

A strong tidal current is always found, except at slack water, in Moser Channel in the vicinity of the bridge, and during spring tides there are overfalls which may swamp a small boat. This tidal current is caused by the differences in the range and in the time of tides on the south and north sides of the keys. On the south side the extreme rise and fall is about 12 feet and on the north side about 312 feet. High and low water may occur on the south side as much as three to four hours before they occur on the north side. Winds also affect the currents very noticeably. The northerly current is increased by easterly winds and the southerly current by westerly winds, due to the effect of these winds in driving out or piling up, respectively, the waters in Florida Bay. The flood current runs northward and the ebb current southward through the draw of the bridge.

From the drawbridge crossing Moser Channel a 356° true (N. 1⁄2 W. mag.) course for 34 miles leads to a position 250 yards westward of a beacon No. 2. Then steer 19° true (N. by E. 11⁄2 E. mag.) for 3 miles, then change course to 354° true (N. 34 W. mag.) for three-fourths mile, which will lead 400 yards westward of beacon No. 1, which marks the northern edge of a 3-foot shoal. Continuing on this course for 25 miles leads 1/2 miles off Cape Sable, Northwest Cape.

Cape Sable, on the north side of Florida Bay, is the southwestern point of the mainland of Florida. It is low and wooded and has three points known, respectively, as East Cape, Middle Cape, and Northwest Cape.

From Northwest Cape the coast trends about north for 20 miles, and then northwestward for 30 miles to Cape Romano. For the greater part of this distance it is broken by innumerable small islands and keys, known as the Ten Thousand Islands, among which is a network of small rivers and bayous leading to the interior. The islands and keys are generally lumps of mud, low and densely wooded, and nearly impossible of identification by a stranger. They

are small in size, mostly awash at high water, and fringed with oyster reefs.

The depths for a distance of 10 miles from the coast are shallow, and for 21⁄2 miles from the coast there is found a depth of 7 feet (2.1 m.) or less. With local knowledge 3 to 7 feet (0.9 to 2.1 m.) can be carried into many of the rivers, but this part of the coast is visited only occasionally by light-draft motor yachts and small craft from Key West and Marco. These vessels seek shelter from gales by entering the rivers or bayous, or by running inshore as close as their draft will permit and anchoring where they find soft bottom.

Ponce de Leon Bay is a nearly rectangular bight, 2 miles wide by 112 miles long, in the west coast of Florida, 7 miles north of Cape Sable Northwest Cape. Shark Point, on the north side of the entrance, and the point on the south side are heavily wooded to the water's edge, and stand out in bold relief against the tree line at the head of the bay. The head and the northern part of the bay are shallow, but there is a good and convenient anchorage for vessels of 6 feet. (1.8 m.) draft in the southern half of the entrance, from one-fourth to one-half mile northwestward of the southern shore. Several narrow streams empty into the head of the bay.

Shark River discharges into Ponce de Leon Bay at its head, through two mouths, close together and about east-northeast from the south side of the entrance. These mouths are not easily distinguished from the other passages through this mangrove-fringed shore. The two branches of Shark River meet at a point about 2 miles inland, where there is an old wharf and abandoned mill. They are navigable for a draft of 6 feet (1.8 m.) to this point. Many yachts and small craft come to Shark River during the winter season for the fishing and hunting, and usually take a guide at Fort Myers or at Marco. The river, because of its intersection by many creeks and bayous, is difficult for a stranger.

Directions, Ponce de Leon Bay.-The shore from Northwest Cape to Ponce de Leon Bay can be followed at a distance of 1 mile until the south side of the entrance bears northeast. Then follow this shore at a distance of three-eighths to one-half mile, and when the coast south of the little river (1 mile south of the bay) is shut out, anchor in 7 to 10 feet (2.1 to 3 m.). Approaching from northward, keep at least 3 miles off shore until a northeast course will clear the south shore of the bay from three-eighths to one-half mile, and then stand in on this course until the coast south of the little river is just shut out. Here there will be shelter from winds east of north or south, and the shoal northwest of the position will afford considerable protection from that direction. Boats drawing over 4 feet (1.2 m.) should not proceed farther into the bay until an examination has been made. On account of the absence of any distinguishing marks, no directions that would be of use to a stranger can be given.

Seminole Point (locally known as Plover Point) and Pavilion Key, 24 and 30 miles, respectively, northward of Northwest Cape, are fairly prominent when coming up the coast at a distance of 2 or 3 miles from it. Seminole Point is the southwest end of the southern one of two small keys lying 111⁄2 miles from the mainland, and is the most westerly land seen until Pavilion Key is picked up. After