Manual of the Geology of India. 81 
tions being everywhere considered in ascending order. This division 
is based upon the very remarkable, but truly natural subdivision of 
India, on geological as well as geographical grounds, into two areas, 
divided from each other by the great alluvial spreads of the Indo- 
Gangetic plain, and styled, from their respective positions, the 
Peninsular and the Extra-Peninsular areas. This bipartite sub- 
division greatly simplifies the treatment of the geology of India as a 
whole. 
The geological formations recognized differ as greatly in their 
character in the two great areas as do the physical features of the 
areas themselves. As the authors point out (Introduction, p. xi) : 
**Throughout the Peninsular area, there is, from the lowest to the 
highest formation, a most remarkable deficiency of fossiliferous 
marine rocks ; the few that occur being almost exclusively found in 
the neighbourhood of the present coast, or else in the deserts between 
the Arvali Chain and the River Indus. With one solitary instance, 
that of some Cretaceous beds occupying a limited area in the Narbada 
valley, no instance is known of marine fossils being found in the 
Indian Peninsula to the south-east of the Arvali range at a greater 
distance than 70 miles from the coast.” 
It is then shown that the absence of marine fossils is not due to 
the alteration of the strata, nor to the absence of rocks suitable to 
have preserved organic remains. 
The oldest marine fossiliferous rocks in the Peninsular area are 
Jurassic, and these are well represented only in Cutch and the 
neighbouring countries. ‘The Cretaceous marine rocks are better 
represented ; although a considerable portion of the series is wanting, 
and the area occupied is very small. The marine beds of the 
Tertiary period are also, so far as is known, very ill developed, or 
wanting, except in Guzerat and Cutch.” Per contra, marine fossili- 
ferous beds are not uncommon in the Extra-Peninsular area—represen- 
tatives of the Silurian, Carboniferous, Triassic, Jurassic, Cretaceous, 
Eocene, and Miocene ages having been found, “and in many cases 
a complete sequence of the different subdivisions of each epoch has 
been detected ; although far less time and labour have been devoted 
to the examination of the country than have been given to the 
Peninsula, and although the geology of the area is in general much 
more complicated, and the task of surveying surrounded by greater 
difficulties.” (p. xii.) 
As the Manual may very likely not come in the way of many of 
the readers of the Grotoaicat MaGaziny, it will be well to quote in 
full the classified lists of formations given by the authors, who 
themselves point out that “the great European subdivisions of the 
geological sequence—Paleozoic, Mesozoic and Tertiary, or Caenozoic— 
are ill adapted for the classification of the Indian beds: and in several 
instances, as will be shown more fully in other chapters of this 
work, the correlation of the strata found in the Peninsula of India 
with the geological series elsewhere is far from satisfactorily 
decided. The lower formations in this list are simply classed as 
Azoic. The subdivisions are not always strictly consecutive ; some 
DECADE II.—VOL. VII.—NO. Il. 6 
