.Ch. X.] EAST INDIAN ARCHIPELAGO. 133 



western range consists in great part of formations of the most 

 modern period. It will be remembered, that many parts of 

 this region have been subject to violent earthquakes ; that in 

 St. Vincent's and Guadaloupe there are active volcanos, and 

 in some of the other islands boiling springs and solfataras. In 

 St. Eustatia, there is a marine deposit, estimated at 1500 feet 

 in thickness, consisting of coral limestone alternating with beds 

 of shells, of which the species are, according to Maclure, the 

 same as those now found in the sea. These strata dip to the 

 south-west at an angle of about 45, and both rest upon, and are 

 covered by, cinders, pumice, and volcanic substances. Part of 

 the madreporic rock has .been converted into silex and calced- 

 ony, and is, in some parts, associated with crystalline gypsum. 

 Alternations of coralline formations with prismatic lava and dif- 

 ferent volcanic substances also occur in Dominica and St. 

 Christopher's, and the American naturalist remarks, that as 

 every lava-current which runs into the sea in this archipelago 

 is liable to be covered with corals and shells, and these again 

 with lava, we may suppose an indefinite repetition of such 

 alternations to constitute the foundation of each isle. 



We do not question the accuracy of the opinion, that the 

 fossil shells and corals of these formations are of recent species, 

 for there are specimens of limestone in the Museum of the 

 Jardin du Hoi at Paris, from the Antilles, in which the im- 

 . bedded shells are all or nearly all identical with those now 

 living. Part of this limestone is soft, but some of the 

 specimens are very compact and crystalline, and contain only 

 the casts of shells. Of 30 species examined by M. Deshayes 

 from this rock 28 were decidedly recent. 



Honduras. Shells sent from some of the recent strata of 

 Jamaica, and- many from the nearest adjoining continent of 

 the Honduras, may be seen in the British Museum, and are 

 identified with species now living in the West Indian seas. 



East Indian Archipdacjo. We have seen that the Indian 

 ocean is one of the principal theatres of volcanic disturbance. 

 We expect, therefore, that future researches in this quarter of 



