478 
Mr. Buckland on the Geology of 
ing specimens of primitive rocks consist of a portion of soft crystal- 
lized talc, apparently from a rock of serpentine, and a fragment of 
slaty hornblende rock. 
2. Secondary Rocks . 
The secondary rocks are varieties of sandstone wholly destitute 
of organic remains, and composed of grains of bright quartz inter- 
mixed with decayed felspar of a white colour more or less strongly 
tinted with red oxyde of iron ; some varieties of the same sand- 
stone are compact and laminated, forming a hard sandstone slate. 
These sandstones appear to be derivative from the destruction of 
granite rocks ; and may probably form subordinate beds in a more 
decidedly characterized sandstone, which is said to constitute a 
large proportion of a hill called St. George's, in this same district. 
The sandstone of St. George’s Hill is of an intensely bright brick 
red colour, and composed of fine grains of quartz loosely adhering 
by a cement of red oxyde of iron, and occasionally of ferruginous 
clay. In some specimens it is united by shining hsematitic iron. 
Brilliant grains of mica appear dispersed irregularly throughout the 
sandstone. Its intense redness gives it a very marked and decided 
character, and connects it with the enormous tracts of a similar 
formation which occur in the neighbourhood of the Cape of Good 
Hope, and which appear also to form the base of many of the 
great sandy deserts of Africa and Asia. It resembles in every 
particular of its colour and composition the newer red sandstone of 
the English series. 
In the same hill of St. George's, there are found rocks of clay 
porphyry, having grains of glassy quartz disseminated through a 
matrix of purple felspar spotted with dirty white ; this porphyry 
nearly resembles that which, at Newton-Glens in the county of 
