The islands of the Caribbean chain have been occupied by European colonists for several hundred years, yet they cannot even at the present day be said to be thoroughly known or sufficiently explored. Though small, they are for the most part mountainous, and present usually a ridge or backbone of high land forming the main axis of each island, with sharp spurs on each side running down to the sea. Cultivation is practically confined to the lower grounds, where alone there are goodroads, and the interior is covered with dense tropical forest, the aspect of which varies greatly with the altitude, and through which there are only rough bush paths. The valleys are usually very deep and narrow, and the steep slopes are covered with plantations of arrowroot, limes, cocoa, coffee, banana or plantain, while most of the level alluvial ground in the valley bottoms is given up to the growth of sugar cane. In all the British islands, at any rate, the principal peaks and ridges have been ascended, and the main features of the country are delineated on the Admiralty charts, which are the best, and in fact the only available maps. As regards the coast-lines and the lower grounds generally, they are very accurate; but in theinterior only the more important points, the principal mountain summits and the like, have had their position sufficiently determined. The rest of the country has apparently been sketched in more or less carefully—but many of the details as, for example, the courses of the smaller streams, and the number of their branches, cannot be relied on. The want of a good map on a fairly large scale is a great drawback in geological work, and prevents the structure of the country being laid down with anyapproach to minuteness.