NASUBATTA ISLAND-LUMBUCAN ISLAND.

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the same velocity, from to 2 knots, in the opposite direction. The mean velocity observed for thirteen consecutive hours was 13 knots.

NORTH CHANNEL is 4 miles wide between Nasubatta and Canabungan Island Reefs and 6 miles wide between Roughton Reef and the reefs extending 13 miles off Gabung and Byan Islands. In the fairway there are depths of above 100 fathoms in places.

Caution. The only difficulty likely to arise in the navigation of this channel by a sailing vessel will be caused by the tidal stream when combined with the current which runs with considerable velocity during the strength of the monsoons, requiring a favorable breeze to enable vessels to make headway against it. But no danger is likely to occur if they keep northward of the deep water, where there is anchorage.

NASUBATTA CHANNEL is 5 miles wide between Roughton Reef and Comiran Danger Bank, with depths of above 100 fathoms in the fairway. In navigating this channel it is only necessary to guard against the effects of the tidal stream, which, when combined with the current, sweeps through it in the direction of North Balabac Strait with considerable velocity at times.

Comiran Danger Bank, 2 miles in length east-northeast and westsouthwest and 1 mile in breadth, includes within its limits Comiran Island and two shoals.

Comiran Island, 80 feet high, lies 7 miles S. 27° E. (S. 29° E. mag.) from Nasubatta Island and 8 miles from the coast of Balabac. It is small, wooded, and surrounded by a reef extending 200 to 400 yards from the shore. Turtle in great numbers resort here at times.

Shoals.—A shoal nearly mile in extent with 2 and 3 fathoms water lies southwestward of Comiran Island, its outer edge being distant nearly 14 miles, and another shoal, about the same size, having 2 to 3 fathoms, lies about the same distance in an easterly direction. Both are fairly steep-to. A bank about 1 mile in extent, with general depths of 6 to 8 fathoms, has a patch of 43 fathoms on its south side, midway between Comiran Island and the east end of Lumbucan Island. There is also a patch of 6 fathoms in the channel northward of it.

COMIRAN CHANNEL is over 3 miles wide between the dangers surrounding Lumbucan and Comiran Danger Bank, with depths of 15 to 25 fathoms in the fairway on either side of the bank mentioned above. It is not recommended, as there are other and better channels, though there seems to be no difficulty in navigating it. Cape Melville Light, bearing S. 72° W. (S. 70° W. mag.), apparently leads through.

Lumbucan Island, about 100 feet high, is about mile in length and wooded. It is surrounded by a reef, and shallow water of a less depth C. and G. S. charts Nos. 4309, 4720.

than 3 fathoms extends 13 miles southwestward and over 1 mile northeastward of it. At 2 to 3 miles northeastward of the island on the same bank are the Northeast Shoals with depths of 12 to 3 fathoms. At ? miles eastward of the island are patches of 3 to 5 fathoms and 1 mile southward is a shoal with 1 to 3 fathoms, known as South Shoal. The island and all dangers stand on the Lumbucan Danger Bank. A sounding of fathoms, position doubtful, is shown on the charts, 2 miles S. 10° W. (S. 8° W. mag.) from the west end of Lumbucan Island.

LUMBUCAN CHANNEL, lying between Lumbucan Island and Bank on the north and Ellis Shoal and Simanahan Reef on the south, is from 4 to 5 miles wide, with depths of 13 to 25 fathoms, and apparently free from danger. Doorly Patches divide the channel at its eastern end, but the least known depth over them is 6 fathoms and they are steep-to.

Ellis Shoal, situated about 6 miles S. 20° W. (S. 18° W. mag.) from the west end of Lumbucan Island and in the western approach to Simanahan Channel, is composed of coral, nearly 3 miles in length east and west and 1 mile in breadth. It has a least depth of 23 fathoms near its center, from which Balabac Peak bears N. 30° W. (N. 32° W. mag.). distant 14 miles.

Simanahan Reef, situated 7 miles S. 48° E. (S. 50° E. mag.) from the east end of Lumbucan Island, lies on the center of a coral bank 5 miles in length by 1 mile in breadth. The reef, dry at low water to about 1 mile in extent, has a sand bank near its center which is just below the surface at high water. This serves, even when covered, from the light color of the water over it, to point out the position of the reef from some distance. The shallow part of the bank, under a depth of 3 fathoms, encompassing the reef, is about 3 miles in extent.

SIMAHANAN CHANNEL, between Simahanan Reef and Great Danger Bank, is apparently free from danger with depths of 23 to 30 fathoms. All that is necessary for its safe navigation is to pass about mile southward of the reef on an East or West course, avoiding Ellis Shoal, but occasion can seldom arise to render this a convenient channel by which to proceed.

Great Danger Bank comprises many reefs among which no vessel should venture. It is 14 miles in length in a west-northwest and opposite direction and 7 miles in breadth at the northwest end, gradually decreasing toward its southeast extremity. On the southeast reef is a sand cay.

Southeast Shoals comprises several coral patches situated near the southeast extremity of the bank, extending over a space about 2 miles in length, with depths of 12 to 4 fathoms, the shallowest being situated S. 80° E. (S. 82°. E. mag.), distant 3 miles from Sand Cay.

NORTHEAST SHOALS-LOXDALE SHOAL.

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Sand Cay, the only conspicuous object marking any part of the bank, stands at the southern side of it, about 4 miles westward of the southeast extremity. The cay is situated near the center of a coral reef, 3 miles in length, from each end of which shallow water (under 3 fathoms) extends mile, with patches of 3 to 5 fathoms beyond, and in a northerly direction, also, nearly as far as the Middle Shoals.

Northwest Shoals, situated at the northwest extremity of the bank, occupy a space of about 5 miles in length, with depths of 1 to 3 fathoms.

North Patches, two in number, lie near the north edge of the bank, with 3 fathoms least water.

Middle Shoals are a cluster of coral patches forming the middle of Great Danger Bank. They cover a space of about 6 miles east and and west, with as little as 2 fathoms in one or more places.

MIDDLE CHANNEL, separating Great Danger Bank from Mangsi Danger, is 1 mile wide at its narrowest part, with depths of 16 to 33 fathoms in the fairway.

Ray Bank, of sand and coral, is 1 mile in length, mile in breadth, and steep-to, with a least known depth of 4 fathoms near its center. It lies on the north side of the approach to Middle Channel and 6 miles westward of Northwest Shoals on Great Danger Bank, with Balabac Peak bearing N. 19° W. (N. 21° W. mag.), distant 16 miles from the 4-fathom spot.

Directions.—Middle Channel lies out of the usual track of vessels, but may be used if necessary. From a position about 2 miles south of Sand Cay steer N. 69° W. (N. 71° W. mag.); when Salingsingan Island, on Mangsi Danger Bank, is abeam, distant about 1 mile, the course should be altered to N. 79° W. (N. 81° W. mag.); when Balabac Peak bears N. 10° W. (N. 12° W. mag.) all dangers will be passed and the course may be shaped as desired.

MANGSI DANGER BANK, situated southward of Great Danger Bank, from which it is separated by Middle Channel, includes within its limits. the Mangsi and Salingsingan Islands, with the dangers adjacent; also Loxdale, Jessie, and many smaller shoals. This bank is 10 miles in length in an east by south and opposite direction and 4 miles in breadth at the eastern end, tapering to the western extremity.

Loxdale Shoal, at the west end of the bank, is a coral shoal nearly 13 miles in length and from 600 to 1,000 yards in breadth, with 2 to 3 fathoms of water, and fairly steep-to. From the west end of this danger Balabac Peak bears N. 24° W. (N. 26° W. mag.) and Salingsingan Island S. 85° E. (S. 87° E. mag.).

C. and G. S. charts Nos. 4309, 4720.

Salingsingan Island, situated S. 73° W. (S. 71° W. mag.), distant 5 miles from Sand Cay, on Great Danger Bank, is composed of sand and coral and covered with trees. It is rather more than mile east and west and 200 yards wide. A shoal nearly awash in parts stretches off mile eastward and 13 miles westward from the island, the breadth of the latter being nearly 1 mile.

Jessie Shoal, with a least depth of 6 feet, lying 24 miles S. 65° E. (S. 67° E. mag.) from Salingsingan Island, is 13 miles in length and mile in breadth. This danger is situated on the east part of the bank, and shallow patches outlie its extremities.

North Mangsi Island, situated about 2 miles southward from Salingsingan Island, is covered with trees, which rise to an apex near the center, 130 feet above high water. The island is mile in length and from its a east end reefs and shoals extend, beyond those projecting from South Mangsi, for a distance of 24 miles, and some patches of 4 to 7 fathoms mile farther eastward. From the west end a line of reefs extends in a N. 70° W. (N. 72° W. mag.) direction for 3 miles.

South Mangsi Island, covered with trees, is round, about mile in diameter, and stands on a reef which extends from it 1 mile eastward, 1,200 yards westward, and less distances in other directions.

Mangsi Great Reef, situated southwestward from Great Danger Bank, from which it is separated by a channel more than 1 mile wide, is 5 miles in length in an east and west direction by 23 miles in breadth and steep-to on its southern side. It is nearly everywhere covered at high water, but a sand cay upon the eastern part is generally visible from aloft when near the edge. At low water the reef presents a vast expanse of coral and sand, with lagoons here and there.

From the west end of the reef shallow water, under 10 fathoms, extends about 2 miles in a west-southwest direction, with irregular depths; the least known is 4 fathoms, but this locality should be avoided. Banguey Peak bearing southward of S. 25° W. (S. 23° W. mag.) leads westward of it.

Kestrel Rock.-H. M. S. Kestrel passed over a patch with 5 fathoms water eastward of Mangsi Channel, with Banguey Peak bearing S. 60° W. (S. 58° W. mag.) and the southwest extremity of South Mangsi Island N. 63° W .(N. 65° W. mag.). Soundings of 8 fathoms were obtained by H. M. S. Comus, in 1882, on a shoal about 1 mile southward of Kestrel Rock. Caution should be exercised while in this neighborhood.

Rock. A rock covered at high water and marked position doubtful is shown on some charts in approximately lat. 7° 28′ 30′′ N., long. 11 32' E. No further information in regard to this rock is available.

SALINGSINGAN ISLAND-MAIN CHANNEL.

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MANGSI CHANNEL, separating Mangsi Great Reef from Mangsi Danger Bank, is 1 mile wide at the narrowest part, where the depths are irregular. It is deep throughout, having from 18 to 33 fathoms in the fairway. The reefs on the north side are steep-to; Mangsi Great Reef, forming the south side, is less so.

Directions.-Navigators will rarely have occasion to use this channel, but in case of necessity the following directions may be of assistance: With a proper lookout no difficulty will be found in passing safely through. Coming from westward having sighted the Mangsi Islands bring the center of South Mangsi to bear S. 75° E. (S. 77° E. mag.) and steer for it; when the west end of North Mangsi bears N. 65° E. (N. 63° E. mag.) steer. S. 45° E. (S. 47° E. mag.), passing midway between South Mangsi and the Great Reef.

MAIN CHANNEL, between Mangsi Great Reef, northward, and Banguey Island, southward, is 5 miles wide, but the navigable width is contracted to 1 miles by reefs extending northward from Banguey Island. Vessels coming from southwestward and bound through Balabac Strait during the northeast monsoon will find this channel the most convenient. Directions. When approaching from westward do not bring the north hill on Banguey Island to bear eastward of S. 72° E. (S. 74° E. mag.) until Siagut Point, the northern point of Balambangan Island, bears South (S. 2° E. mag.). From a position 2 miles northward of Siagut Point a N. 79° E. (N. 77° E. mag.) course should carry a vessel about mile southward of Mangsi Great Reef. The light-green color of the water over this reef will, even at high tide, enable a good lookout aloft to make out the edge sufficiently far off to permit a vessel being guided past it at a safe distance. From about mile off its south end steer to pass about 2 miles southward of South Mangsi Island and the same distance northward of Kestrel Rock; thence a course about East until the Muligi Islands bear S. 45° E. (S. 47° E. mag.), when they may be steered for. This is the route usually adopted by vessels bound to Jolo and Sandakan, the channels southward being much encumbered with shoals.

WEST COAST OF PALAWAN.

The west coast of Palawan is fronted by a bank studded with innumerable shoals and reefs. The 100-fathom curve, marking the outer edge of this bank, is about 20 miles northwest of Cape Buliluyan. From this position it trends in a general direction N. 35° E. (N. 33° E. mag.), and is about 26 miles off at the northern end of the island. This bank has not been thoroughly surveyed and new dangers are frequently reported. Navigators are advised to keep outside of the 100-fathom

C. and G. S. chart No. 4720.