Tee 
Manual of the Geology of India. 127 
plagioclastic felspar is here and there to be recognized; the horn- 
blende very irregular in outline. I believe, however, that we may 
safely affirm the rock to be a true Diorite. There isa fair quantity of 
a pale yellowish-brown somewhat earthy-looking mineral, with a 
fairly-marked prismatic cleavage; occasionally in well-defined 
crystals, which from their outline and optical properties appear 
to be monoclinic: microlithic crystals, apparently of a similar 
mineral, are often contained in them. They may be epidote, but are 
not in that case characteristic examples; they have also some 
resemblance to sphene. 
REVIEWS. 
——— id 
J.—A Manvat or tHe Geonoey or Inpra, ete. (Second Notice, 
continued from the Gror. Mac. for February, 1880, p. 85.) 
Strongly contrasting though the several formations are which 
make up the two great groups of the Peninsular and Extra- 
Peninsular rocks—they are yet found in a few places to be in actual 
juxtaposition, individual members of each group occurring outside the 
geographical limits of the two areas:—for example, in Cutch and 
Kattywar, certain marine Extra-Peninsular beds are interstratified 
with typically Peninsular formations. Again, in Sind, a representa- 
tive of the Deccan trap occurs intercalated between the marine Eocene 
and Cretaceous rocks. 
Two other Extra-Peninsular localities are named by the authors, 
in which Peninsular rocks are found. ‘One of these is at the base 
of the Himalayas, in Sikkim and Bhutan, where fossiliferous Damida 
(Lower Gondwana) beds occur. The other is in the Assam Hills 
(Khasi and Garo), where representatives of the metamorphic and 
Cretaceous (marine) rocks of the peninsula, and in all probability of 
the transition beds, and of the Rajmahal traps, are found. But in 
the first instance the relations between such Himalayan rocks as are 
associated with the Damiadas and those of other parts of the Hima- 
layas are extremely doubtful ; and it is not even conclusively settled 
whether the Himalayan rocks in question are higher or lower in 
position than the Damada beds themselves; and in the Assam hills 
none of the older Himalayan formations have been detected ; they 
appear to be replaced by Peninsular types” (p. xv). 
A very interesting and important point of contrast between the 
two great areas, and one throwing great light upon their geological 
history, is to be found in the absence of any traces of disturbance in 
late geological times in the Peninsular area; “a feature which (as 
Mr. Blanford pointedly remarks) abruptly distinguishes the whole 
area from the remainder of Asia” (p. vi). He contends that the prin- 
cipal dividing ranges of the Peninsular area “are merely plateaus, or 
portions of plateaus, that have escaped denudation. There is not 
throughout the length and breadth of the Peninsula, with the pos- 
sible exception of the Arvali, a single great range of mountains that 
coincides with a definite axis of elevation; not one, with the excep- 
