tery, instruments of human art and industry ; and, at Gua- 

 daloupe, even human skeletons of the Carib race. The 

 negroes of the French colonies call these banks " Maconne- 

 bon-Dieu." ( 244 ) In Lancerote, one of the Canary Islands, 

 a small bank of oolite, which, notwithstanding its recent 

 formation, resembles the Jura limestone, has been recog- 

 nised as a product of the sea and of tempests. ( 245 ) 



The composite rocks are determinate associations of certain 

 simple minerals, such as feldspar, mica, silex, augite, and 

 nepheline. Rocks very similar to those of the earlier periods, 

 and composed of the same elements, but differently grouped, 

 are now produced under our eyes by volcanic processes. 

 "We have already remarked, ( 246 ) that the mineralogical cha- 

 racters of rocks are wholly independent of their geographical 

 distribution ; and the geologist recognises with surprise, in 

 opposite hemispheres, and in very dissimilar climates, the 

 familiar aspect, and the repetition, even in the most minute 

 details, of the successive members of the silurian series, and 

 the precisely similar effects of contact with erupted augitic 

 masses. 



We will now take a nearer view of the four fundamental 

 classes of rocks, which correspond to the four phases or 

 modes of formation presented by the stratified and unstrati- 

 fied portions of the earth's crust : and, first, in the endoge- 

 nous or erupted rocks, designated by some modem geolo- 

 gists by the terms massive and abnormal rocks, we distin- 

 guish as immediate products of the active subterranean 

 forces, the following principal groups : 



1. Granite and syenite, of very different ages. The 

 granite is often the more recent rock, traversing the 



