The island of Dominica is situated in lat. 15° 20′ N., and long. 62° 30′ W., and lies almost midway between the French islands of Guadeloupe (on the north) and Martinique (on the south). In the northern channel the Antillean plateau is submerged to a depth of about 2,100 feet, but in the southern a deep embayment entering from the west reaches a maximum depth of 6,600 feet. Some miles to the south-east of Dominica, however, the sea floor rises to within 270 feet of the surface, while the Madiana banks, east of Martinique and north of Barbados, are submerged only to about the dame depth. Lying as they do between the sedimentary parts of Antigua, Guadeloupe, and Barbados it would be interesting to ascertain, if possible, by boring, whether these banks are of a sedimentary nature in contrast to the volcanic nature of the main range of islands. On both the windward and leeward sides Dominica rises precipitously out of the sea, but this is more accnetuated on the leeward side where within six or seven miles of the shore the sea bottom reaches a depth of over a thousand fathoms. The preciepitous nature of the sea floor and the absence, of any sort of harbour at Roseau—the capital—render anchorage even at favourable times a very precarious matter, and one of great difficulty and danger in rough weather.