ON THE GEOLOGY OF THE NORTH-EASTERN WEST-1NDIA ISLANDS. 21 



Lin, Crepidula aculeata Chemn, Strombus Gigas Lin and some corals. This proves that at 

 a recent time the island has been elevated from the sea. Along the whole southern coast, 

 from Basseterre to the old town of Old Road, occur only volcanic tufas, cinders and boul- 

 ders, sometimes of a considerable size. Northwest of Basseterre and above Old-Road is a 

 wild, picturesque mountain, S:t Patrick's Hill, of about 1,010 meters. It seems to be a vol- 

 canic centre. Northwest of S:t Patrick's Hill is situated the highest mountain in the island, 

 Mount Misery, with summits of 1,131 meters. The mountain is described as havino' in the 

 summit a crater with a lake, hot springs and fumarols, exhaling sulphuretted hydrogen, which 

 by oxydation produces beautiful crystals of sulphur. 



At the foot of Mount Misery there is in Brimstone Hill a white limestone rock of 

 considerable size, surrounded in all directions by loose volcanic rocks. I have not seem 

 in it any trace of stratification. The rock has the appearance of chalk and contains many 

 fossil shells and corals, the greatest number in the form of casts. I have found about 

 43 different mollusca, all of species still living in the Caribbean Sea, except a single spe- 

 cimen of a Modiolaria, closely related to a northern still living species. Among the fossil 

 shells one of the most cominon is Tellina Gruneri Phil., also occurring in the miocene 

 strata of Cuba (T. Sagrse d'Orb) and Puerto Rico, and still living in the Caribbean Sea, 

 but very rare. The greatest number of still living species indicate the recent time, at 

 which the deposit was formed, and the formation may probably be dertermined as the 

 newest pliocene, or post-pliocene. The volcanic rocks of S:t Kitts are trachytic, probably 

 oligoklase-trachyte. They have a grayish or reddish colour and contain white crystals of 

 glassy feldspar and some hornblend. 



Not having visited the other volcanic islands belonging to the same range as S:t 

 Kitts, viz. Nevis, Redonda and Montserrat, I will now discribe the eastern leeward 

 islands. 



Sombrero. During my travels in the West-Indies 1 had no opportunity to visit 

 this small island, remarkable for the phosphate of lime, which in latter years has been 

 taken from it, but from Dr A. v. Goes of S:t Bartholomew I have obtained some informa- 

 tion about the geology of the island as well as several specimens. This small island is a 

 very flat cay formed of a härd white limestone, full of fossils in the form of casts or 

 impressions. The limestone is intersected by veins running N. W. — S. E. and containing 

 phosphate of lime of variable appearance. Some of the specimens are transparent yellow, 

 without any trace of crystalization, some have been corals and shells whose carbonate of 

 lime is metamorphosed to phosphate. The origin of the phosphoric acid is difficult to 

 explain, but it is supposed that the island, which was formerly inhabited by numerous 

 birds, has been covered by guano, of which the phosphoric acid has been dissolved and 

 penetrated the limestone-rock. 



The fossils of the limestone rock are very difficult to determine, as most of the 

 specimens are fragments of casts and impressions. Nevertheless most of the mollusca 

 seem to belong to species still living in the Caribbean Sea as Tellina fausta Gold, Ceri- 

 thium litteratum Born, C. caudatum Sow., Fissurella Listeri dOrb. etc; but among these 

 shells occurs in great numbers one species of Bulla, which seems to be B. granosa Sow, 

 now extinct and found in the miocene beds of S:t Domingo and Puerto Rico. On this 



