It is about 112 miles in length and in some parts 1/2 mile in breadth, but of irregular shape and with several small bays indenting its shores. The channel between the entrance reefs is about 100 yards wide, well buoyed, and has a least depth of 28 feet on the Inner Harbor Range. The shores of the harbor are hilly and largely covered with a scrubby forest growth, excepting where cleared for houses or planting.

San Ildefonso is on the hillside on the northeastern side of the harbor. There is a wharf in front of the village, but it is in bad repair. There are scattering houses on the hill back of Point Cabras. The village of Culebra is near the head of the harbor and can be seen from the outside, where Seine Bay bears about northeast. A boat. channel has been cut from Seine Bay through the isthmus to the head of Great Harbor.

Supplies. Only a small amount of supplies, such as fruit, vegetables, and eggs can be obtained, and there are no facilities for obtaining water. There is no stock of coal.

Yellow Shoal is about 500 yards in length and has a least depth of 8 feet of water. Its southwestern extremity is marked by a red nun buoy, lying 1,250 yards 88° true (E 14 S mag.) from Point Soldado.

Grouper Shoal, about 500 yards northward of Yellow Shoal, has 4 feet least water and is about 700 yards in length east and west. Its eastern extremity is marked by a black can buoy. About 200 yards westward of its outer limit is another shoal, with 20 feet of water. A shoal, with 21 feet of water, lies about 250 yards west-southwestward from here with a 24-foot shoal close to it.

Shrimp Shoal, about 300 yards in length east and west, with a least depth of 9 feet, lies 350 yards southward from Point Vaca. A red nun buoy marks the southern edge of it.

Snapper Shoal, lying 600 yards westward of Point Vaca, has 8 feet least water. A shoal with a depth of 20 feet, lying westward of it, is marked on its southwestern edge by a red nun buoy.

Middle Ground, with 22 feet least water, lies 1/4 mile west-southwestward from Snapper Shoal. A black can buoy marks its western edge. A white diamond-shaped beacon is erected on the extremity of Point Colorada and a square white beacon 750 yards 296° true (NW by W 3% W mag.) from it. These two beacons in range lead between Shrimp and Grouper shoals as far as Middle Ground.

A white diamond shaped beacon is erected at the head of the harbor, 1/4 mile westward of San Ildefonso, and a square white beacon 1,200 yards 323° true (NW by N mag.) from it. These two beacons in range lead through the entrance channel to Great Harbor from their intersection with the Point Colorada Range.

DIRECTIONS, GREAT HARBOR.-Vessels approaching from southward should bring the left tangent of Point Vaca to bear 8° true (N by E mag.) before the southern end of Southwest Cay closes behind Point Soldado, and steer for it until close up to Shrimp Shoal buoy. Then swing on to Point Colorada Range, course 296° true (NW by W % W mag.). When nearly up to the Middle Ground buoy, steer in on the inner harbor range, course 323° true (NW by N mag.) between the red and black buoys marking the entrance reefs. When Point Carenero bears about east open the range to the westward and anchor according to draft. It will probably be necessary for sailing vessels to warp out.

From the southeastward bring Point Vaca in range with Mount Resaca, bearing about 322° true (NW by N mag.) and continue on this course past Los Crespos Shoal Buoy, until Point Colorada Range comes on; then follow as directed above.

Grampus Shoals is a group of small coral heads rising from a bank of 10 fathoms and lying from 2 to 4 miles from the southeastern extremity of Culebra. The southern head, on which there is a depth of 334 fathoms, lies with Point Soldado in range with the southern extremity of Southwest Cay, bearing 293° true (NW by W 5% W mag.). About 3/4 mile northeastward from this is a small cluster of heads with as little as 32 fathoms on them; these are the most eastern, and lie about 4 miles 163° true (S by E % mag.) from Cape Passage, Culebrita Island. The southern of the innermost or western heads, with 3 fathoms of water, lies about 314 miles 105° true (ESE 14 E mag.) from Point Soldado.

A red nun buoy marked "Grampus Shoals " lies in about 10 fathoms on the southern side of Grampus Shoals.

A black can buoy marks the northern edge of the innermost or western head of these shoals.

Grampus Channel lies between this western knoll and the long line of reefs extending south-southwestward from Culebrita; it is a clear navigable channel nearly 1 mile wide and is marked by buoys.

In the Grampus Channel the tidal current sets diagonally across, the flood to the southward and westward and the ebb to the northward and eastward.

DIRECTIONS. To pass to the southward of Grampus Shoals keep on or southward of the line of Sail Rock and Signal Hill on St. Thomas Island until Palada Cays show eastward of Cape Passage, the northeast point of Culebrita Island. Grampus Shoal will then be cleared and the course can be shaped as desired.

Point Soldado, the southern point of Culebra Island, is wooded and terminates in a rocky bluff about 35 feet high. It is prominent when seen from the eastward or westward, from which directions it appears as a ridge. Snug Bay, 111⁄2 miles northwestward of Point Soldado, is a well-sheltered boat harbor; Seine Bay, the next cove northwestward of it, has excellent seine fishing, and a good beach. It is connected by a boat channel with Great Harbor. Scorpion Point, the first prominent point westward of Seine Bay, is low and protruding.

Southwest Cay is 114 miles long north and south, and its wooded peak is 475 feet high. Its north and south ends are high, and joined to the island by low necks. Except when the trade wind is northward of northeast, a fairly smooth anchorage can be had in 8 to 9 fathoms about 1/4 mile off the northwest side of Southwest Cay, with Pillar Rock in line with the north end of Yerba Cay, bearing 289° true (WNW mag.), and the northwest point of Southwest Cay bearing 210° true (SW by S mag.).

There is good anchorage, with the ordinary trade winds, between Southwest Cay and Culebra Island, or farther southeastward, and there are no dangers if Culebra Island between Point Soldado and Scorpion Point be given a berth of 1/4 mile. There is a rocky patch with 7 fathoms 1/2 mile westward of Scorpion Point which should be avoided in anchoring. A good berth will be found in 13 fathoms

with Fungy Bowl in line with the north end of Southwest Cay, and Scorpion Point bearing 98° true (E by S mag.), distant 700 yards. Sailing vessels anchoring northward of this will have some difficulty getting underway on account of baffling winds and strong tidal currents. Small steamers will find a more comfortable anchorage nearer Culebra Island between Scorpion and Stream Points; one of the best is in 5 to 7 fathoms in the middle of the entrance to Firewood Bay, eastward from the north point of Southwest Cay.

Approaching the anchorage between Southwest Cay and Culebra Island from northwestward, the best route for large deep-draft vessels is to pass westward of The Washer, enter Vieques Sound either between Cross and Cactus cays or through Barriles Passage, and pass southward of Southwest Cay. The best channels for sailing vessels are those westward of The Sisters, on account of the variable winds, narrow passages, and greater velocity of the tidal currents between The Sisters and Culebra Island.

Canal de Luis Pena, between the north end of Southwest Cay and Stream Point, is 700 yards wide. There is a coral head with 21 feet of water a little southward of the middle of the passage, and two other heads with 27 and 29 feet of water in it. The strong currents and baffling winds render the passage scarcely safe for sailing vessels. For tidal currents, see page 30. Stream Point, on Culebra Island, has a hill 75 feet high, with reddish bluffs, at the end, and a low neck behind it; there are two low, detached rocks near its end. The channels between Northwest Point of Culebra and the islets and rocks westward of it are safe and easy to navigate in the daytime, as most of the dangers show above water.

The Sisters lie from 3 to 1 mile northwestward of Southwest Cay, and are three islets, as follows:

Yerba Cay, the northernmost, is 65 feet high, and has a smooth grassy slope on the east side and rocky bluffs on the west side. The passage between Yerba and Mono cays is 400 yards wide, with 7 to 8 fathoms in the middle.

Mono Cay, the southwesternmost and smallest of The Sisters, is 45 feet high, grassy on top, and rocky on the sides; there is a low rock close to its southeast side. The passage between Mono and Agua cays should be avoided.

Agua Cay, the southeasternmost of The Sisters, is low in the middle, and 40 feet high at its eastern and higher part. It is rocky, and there are many large bowlders scattered over and near it. A shoal with 5 feet at its end extends nearly 200 yards westward of it toward Mono Cay, and the passage between these cays should be avoided. The passage between Agua and Southwest cays is 3% mile wide, and has depths of 7 to 71⁄2 fathoms.

Black Rock, 3⁄4 mile southeastward from Cross Cay, is a small irregular ledge with a number of heads, the highest 15 feet. The passage between Black Rock and The Sisters is 34 mile wide, with depths of 512 to 9 fathoms.

Cross Cay is triangular in shape, 12 by 1/4 mile in extent, 135 feet high at its west end and covered with scrub and grass. The three points of the cay are high with rocky bluffs, and joined by lower land in the middle. The passage between Cross Cay and Black Rock is clear and over 3% mile wide, with 13 to 14 fathoms in the middle.

Cactus Cay is the westernmost of the chain of islets which extend 314 miles west-northwestward from Southwest Cay. Its greatest diameter is about 400 yards, and it is 95 feet high; there is a bare ledge close to its northwest end. Piliar Rock is a detached, bare pinnacle, 75 feet high, on the south end of Cactus Cay. The passage between Cactus and Cross cays is clear and nearly 34 mile wide, with about 13 fathoms in the middle.

VIEQUES ISLAND.

This island lies nearly 6 miles from the nearest point of the east coast of Porto Rico, and forms the south side of Vieques Sound. It is 18 miles long east and west, and has a greatest width of 32 miles near its middle. A range of hills extends the entire length of the island, and there is a prominent hill at each end-Mount Pirata (981 feet) near its western end, and Mount Jalobre (450 feet) 3 miles from East Point. The island is wooded in places, especially its eastern half and Mount Pirata, but some of the hills are cultivated with sugar cane to their summits. (See fig. 3.)

The population of the island by the census of 1920 is 11,651. The principal products are sugar, horses, and cattle. Vegetables and tropical fruits are grown in sufficient quantities for local consumption. The rainy season lasts from May to October, but the rainfall is less than in the adjacent parts of Porto Rico. The island is subject to drought, and rain water stored in cisterns forms the principal water supply. During normal rain conditions, both the north and south sides of the island westward of Port Mulas have springs and streams, but there is no fresh water convenient for vessels.

There is no harbor on Vieques Island. Vessels frequently call to discharge or load at Port Mulas, and occasionally at Port Real and the west end of the island. There is a heavy surf on the north coast when the trade wind is northward of east, and landing is impossible on the open coast. Boats can generally land at the west end of the island; at Mosquito Landing, Port Mulas, Port Negro, Cano Hondo, Port Salinas, and East Point, on the north coast; and at all the boat harbors and said beaches on the south coast when the wind is northward of east.

Port Mulas is an open bight on the west side of Point Mulas, north coast of Vieques Island, 8 miles eastward of Point Arenas and 10 miles westward of East Point. It is a poor anchorage, with little or no shelter, for vessels. For a distance of 600 yards off Isabel Segunda the port is shoal and has spots with 5 to 9 feet. Small craft of 6 feet or less draft can anchor near the shore, from 200 to 400 yards southward of the lighthouse, with fairly good shelter during ordinary weather. With northerly winds a heavy sea makes into the port, and small craft anchored here are sometimes driven ashore at such times.

Isabel Segunda (post office Vieques) is the principal town of the island, with a population of 3,424, and has daily launch and mail service to Playa de Fajardo. Playa de Humacao is the subport of entry. The principal exports are sugar and cattle. Boats can land at a small pier 300 yards southward of the lighthouse. There are grocery and drug stores in the town. There is communication by heliograph

with the east coast of Porto Rico, and thence by telegraph with other points.

Prominent features.-Point Mulas is a low bluff surmounted by Point Mulas lighthouse and small houses eastward of the lighthouse. The buildings and square brick stack of Santa Maria sugar mill are 5% mile eastward of the lighthouse. An old brick fort with yellow building stands on a hill 12 mile southeastward of the lighthouse. There is a grassy hill 225 feet high, with a few trees near its summit, at the south end of Isabel Segunda. Martineau Hill, a prominent wooded dome 594 feet high, is near the north coast, 214 miles southwestward from the lighthouse. Caballo Blanco is a low, grassy islet 134 miles northwestward from the lighthouse.

The approach to Port Mulas from the westward and northwestward is obstructed by several small shoals lying about 11⁄2 miles from the shore. Comandante Shoal, about 600 yards in extent with from 10 to 17 feet of water over it, lies about midway between Caballo Blanco and the shore southward of it. Corona Reef, awash and 600 yards long east and west, lies about 1/4 miles west-southwestward of Caballo Blanco, with from 42 to 7 fathoms of water in the channel between them. Mosquito Reef, awash, lies 1/4 mile to the westward of Corona Reef. They are both steep-to, and the sea always breaks on them. A shoal with a depth of 17 feet lies nearly 1/2 mile west-northwestward from Mosquito Reef, and a spot with a depth of 25 feet lies 600 yards northward from Corona Reef. Another spot with a depth of 16 feet lies 500 yards southward of Corona Reef. There are also a number of small shoals, with deep water close-to, westward and southward of the reefs. Merail Shoal, with a least depth of 6 feet, lies 3/4 mile southward of Corona Shoal. Pilot. There is a pilot at Isabel Segunda.

Anchorage.-Vessels of the deepest draft can anchor about 3/4 mile northwestward or northward of the lighthouse in 7 to 8 fathoms, and smaller vessels can select anchorage with the lighthouse bearing between southeast and east, distant 1/4 mile or more, in 22 to 30 feet.

The larger steamers (20 feet or less draft), having cargo to discharge or load, anchor about 600 yards from the lighthouse, bearing 120° true (SE by E mag.), with the points on the north coast eastward of it in line, bearing 80° true (E 12 N mag.), in 30 feet. Coasting steamers of 12 feet or less draft anchor about 300 yards from the lighthouse, bearing 97° true (E by S mag.), with the grassy hill (few trees near summit) near the south end of the town bearing 160° true (S by E 12 E mag.), in 21 to 22 feet of water.

Caballo Point, 234 miles eastward of Point Mulas, is rocky and steep-to.

Port Negro is a boat landing 5 miles eastward of Point Mulas lighthouse and 2 miles westward of Cucaracha Rock. It can be entered only by small craft with local knowledge. The entrance through the reefs is about 100 yards wide, with depths of 6 to 18 feet, and is generally indicated by the breakers on either side. There is little anchorage space in the port, the most of it being foul. Point Brigadier, 5% mile westward of the entrance, is marked by a large, rugged, bare

rock close-to.