CHAP. 3.] GENERAL CLASSIFICATION OF ROCKS. 39 
to be really merely the work of time, until they have been traced actually 
‘into connection with one another by the rocks 27 situ, or by the finding 
out of known rocks which may be associated with them. 
This has been done to a certain exggmt with regard to the VINDHYANS; 
aru sate ans. and likewise with the KADAPAH FORMATION. The 
VINDHYANS have been made out by our colleagues 
in Bengal and Bombay to be well below, and to be separated by a 
greater break than exists between most European formations from, 
the Indian TALcHIRS, which are considered to be of carboniferous age. 
This then brings the vinpHyANs low down in the paleozoie period. On 
the other hand, we have found plant-bearing beds resting unconform- 
ably on the kApAPAH ROCKS, the vegetable remains of which Mr. Foote 
recognized as belonging to the Indian RAJMAHALS, and these, according 
to the latest researches, are of lower jurassie age. 
So far, then, all that can be accurately said of the KARNÚL and 
KADAPAH ROCKS is, that they are greatly older than the TALCHIRS, 
which are certainly not younger than the carboniferous epoch of 
European geologists. As far as lithological resemblance goes, the 
structure, mineralogical composition, and general aspect of the KADAPAH 
formation approach closely to that of the Cambrian and Lower Silurian 
of Europe and England. 
But to return to these formations themselves. By the tests of 
superposition and constitution it has been made out that the one series, 
the KARNUL rests unconformably on the upturned edges of the other, 
the KADAPAH; and that each of these formations is divisible into groups 
as follows :— 
KARNÜLS. 
into a set of limestones and shales which may be 
Classifieation of 
EN EEL sub-divided and named thus— 
Nundial shales, 
The Khoond-aw Group... ... : 
Koilkoontla limestones. 
