346 PROF, SPENCER ON THE GEOLOGICAL AND [Aug. 1902,. 
700 and 900 feet was of importance. Morne Bruce, immediately 
behind the town of Roseau, at 400 feet, is a fine illustration. On 
each side of the Geneva-Roseau summit are grand gorges, reaching 
to depths of 400 and 600 feet, clothed with the lovely primeval 
tropical vegetation, such as tree-ferns, ete. Short ravines occur,. 
commencing directly at the coast, and suggesting recent elevation 
of the land. But the larger valleys, such as that of Roseau, are- 
much more open, and have had a longer and more varied history. 
Martinique. 
This island is somewhat larger than Dominica, with the highest. 
point, la Montagne Pelée, in the north, reaching to an elevation of 
4428 feet. The central part of the island is deeply indented by Fort-. 
Royal Bay and the large valley behind it. The soundings show the 
remains of a considerable coastal plain, submerged about 200 feet, 
extending north-eastward from the island. From the higher 
mountain-ridges heavy tuft-beds are seen sloping seaward at angles. 
varying between 10° and 20°. On the southern portion of the: 
island are remains of base-levels of erosion, or modified tablelands. 
St. Lucia. 
This is a smaller island than Dominica. It consists of a central 
dome rising to a height of 4000 feet, and formed of late volcanic 
accumulations. ‘The northern part of the island shows considerable 
antiquity, as its surface, composed of old igneous rocks, has been 
greatly modified by erosion. There is only the suggestion of a 
coastal plain in the fragment of a shelf, submerged to 200 feet, 
extending northward from the island. The peaks upon the south- 
western coast, called the Pitons, attract the main attention of 
travellers. They are simply the remains of a dissected volcanic 
crater, partly rising out of the sea. 
St. Vincent. 
This island is still smaller than St. Lucia. The highest cone has. 
a summit reaching to 4048 feet, but the floor of the crater, covered 
by a lake, is only 1930 feet in altitude, and the rim varies from 
3100 to 3600 feet. This volcano was in eruption in 1812, when 
great quantities of ash were carried to Barbados, more than 100 
miles away. Extending from the interior mountains, are dissected 
sloping surfaces, as in the other islands, but the forms of the 
valleys are more mature than those of Dominica. South-east of 
the island is a considerable coastal plain, submerged to a depth of 
200 feet and less. | ! 
The Grenadines. 
These are simply the remnants of the erosion of the old volcanic 
formations, rising out of an extensive plain now submerged to 
