476 Extracts from the Proceedings of the British 



about 1800 feet ; and over these again is a distinct series of quart- 

 zose grits, conglomerates, and sandstones, in thickness from 1600 

 to 2000 feet. These three groups are unconformable each to the 

 other ; the unconformity between the two lower being, however 

 much less marked than that between the two upper. To the 

 lower group, as having been first recognised and described in this 

 district, the name of " Talcheer" series has been given ; the second 

 group, which, from its imbedded vegetable remains, was proved 

 to be identical with the rocks of the extensive Damoodah coal- 

 field when these were first described, has been denoted the " Da- 

 moodah " series ; while the upper group, supposed to represent 

 the great series of rocks, so magnificently seen in the Mahadeva 

 Hills of Central India, has been called the "Mahadeva " series. 

 Thus these series can be recognised in each of the extensive fields 

 referred to, although with varying developments and thicknesses. 

 At the base of the Talcheer series there is a remarkable bed, con- 

 sisting of very large and only slightly rounded masses of granite 

 and gneiss, imbedded in a fine silt, and occurring under such con- 

 ditions as induce the opinion that the action of ground ice has 

 been the cause of its formation. In the Rajmahal district there 

 is a very limited development of the lower beds, above which 

 unconformably comes the Damoodah series, here exhibiting a 

 greater extension upward than in Cuttack ; but unfortunately the 

 sequence of the rocks is interrupted by the intercalation of several 

 successive floes of basaltic trap, the intervals between which have 

 been marked by the continued and tranquil deposition of the me- 

 chanical rocks going on. These floeS have been repeated six or 

 seven times, and the phenomena of contact are in all cases marked • 

 the upper layers of the mechanical deposits in contact with the 

 trap being in all cases greatly altered, while the lower layers are 

 in no cases changed, but rest unaltered on the degraded surface of 

 the underlying trap. But while the actual physical sequence of 

 the deposits cannot be here traced, the fact of their all belonging 

 to the same great series is attested by the occurrence of some 

 identical fossils throughout. A few species pass upwards through, 

 the series, but there is a very marked change in the general facies 

 of the flora in the upper as compared with the lower portion of 

 the group ; the latter characterized by the abundance of verte- 

 brata, pecopteris, trizzgia,' &c., the former by the abundance of 

 zamia-like plants. The series, therefore, has been divided into 

 Upper and Lower Damoodah rocks. For the details of the struc- 



