26S 
Records of the Geological Surveg of India. 
[vOL. XI. 
the power of the Director of the Geological Survey' of India, for he alone has at 
his command the materials necessary for the construction of a detailed map on a 
larger scale. The geology of India shows, however, so many most interesting 
facts that can only he represented on a Cirrtographic basis, that I have no hesita¬ 
tion in laying down on a small sketch map, even at the risk of many inaccnracies 
in detail, what are at present approximately settled facts. My sole object now is 
to show in bold outlines the geographical distribution of the several formations 
in India, and for that purpose the annexed map is amply sufficient. As the title 
of this essay already show.s, the geological map is not the object in view; it is 
intended only as a basis for the discussion which deals with the geographical 
distribution of fossil organisms. It is only by the absolute want of any general 
geological map of India that I am forced to compile one from existing sources and 
my own experiences, but for this I should have greatly preferred availing myself 
of what already existed.'- 
The peculiarity of the subject demands, besides, a peculiarity in the representa^ 
tion such as has till now been but rarely applied to geological maps. I found 
myself compelled not only to separate the formations accordirrg to their boundaries, 
but also to represent clearly the differences of facies in the formations themselves, 
so that the first glance at the map shoirld give a general A'iew of the distribution 
of the facies. It will be only by this method of representation that one can 
follow with ease the conclusions which I feel myself justified in drawing from the 
geographical distribution of the fossils. 
It has long been knowrr that the different formations in various par-ts of India 
have been dovolo})ed according to very different types, and this diversity attained 
often such a magnitude that it appeared almost impossible to harmonize the 
succession of formations in one regiotr with that obtaining in another. It has 
become customary in India to recognize (following Blanford) two chief types of 
development which were designated as the Himalay.an and Peninsular types: the 
first of these was compared with the Alpine type of the European scale of form¬ 
ations, the second with the extra-Alpine type, without entering into other and 
more special analogies. But several writers in India" had already pointed out that 
probably the greater part of the plant-beds of the Indian Peninsula were of fresh- 
* I base my little map ebiefly on tlio surveys and reports of my former eolleaffues, the members 
of the Geologie.al Sim-ey of India, hut in several cases I could only give the boundaries of form¬ 
ations approximately, as the reports are frequently unaccompanied by maps, e. g., in the region 
south of the great basaltic districts, in the lower course of the Godavari, in Kajpntana, and in Sindh, 
&c. (Vols Xn and XIII of the Memoirs Geological Survey of India were not available to mo when 
preparing the map). For small parts of llehar, the Central Provinces and Rajputana the repre¬ 
sentation is based otdy upon probabilities, as both reports and maps are wanting in these cases. 1 
have no hesitation in thus drawing attention to the deficiencies of my map, for one reason that 
the obiect of the present publication hoes not centre in the mail, for anotlier, tlrnt the inaccuracies 
at the points indicated are probably not of a clmracter to alter materially the general view of tlie 
geological stricture of India which is the aim of the map. 
^ Lately by H. F. Blanford: Quart. Jourii. Geol. Soc,, Lond., 1875, and before him by T. Oldham, 
\V. T. Blanford, and several others. 
