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There is also a narrow strip of deep water only about 8 miles wide, Called the Swatch. It runs in towards the land for a distance of 35 nautical miles, and is of great depth; in some places it is upwards of 100 fathoms. This is evidently the outlet for the freshes of the River Indus, being immediately opposite the Kaha mouth of that river. The deep water is only about 12 miles from the land. There is a similar swatch, but on a much smaller scale, and of les3 depth, opposite the Hujamree Mouth.
By reference to Model Chart, No. 1, it will be seen that there is likewise a patch of deep water running up the Gulf of Cambay, but it has only 21 fathoms water, though its length is 50 nautical miles, and greatest width 10 to 15 miles.
Opposite to Manora Point, and between it and Ras-Muari, there is another submarine bay in 20 fathoms water, as shown by the purple colour on the chart. It is about 35 miles wide, and runs about seven miles inwards towards the land. Unfortunately for the Harbour of Kurrachee, this bay happens to be some miles to the westward of the present entrance to that harbour. Immediately facing the entrance to Kurrachee, there is a long line of shallow water, which continues in a south by easterly direction for a distance of 75 nautical miles. The depth aud width of this shoal of water is only—
5 fathoms for five miles out.
10 do. „ eleven miles out.
15 do. „ sixteen miles out.
20 do- „ fully twenty miles. This gives an average inclination of six feet in a mile, or a gradient of 1 in 900; such a gradient would be considerable in the bed of a confined river, but in the open sea it is comparatively small. This bank or shoal is also formed by detritus brought down by the Indus.
The Harbour of Kurrachee is nothing more than a large lagoon, the set of the tide into it being very sluggish, and not direct, but round a long corner, so to speak, taking as it does three quarters of an hour to travel from the Gisri Mouth to Kurrachee, a distance of only eight miles, and with a tidal rise of but from six to nine feet, and one to two fathoms water at the entrance during low water.
If the long bank opposite to the entrance to this Harbour be formedby the detritus of the Indus (of which there can be little doubt), then the