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part 8.] Lydekker: Fossil Mammalian Faunas of India and Burma. 
Assuming the truth of this hypothesis, we must, in considering the relations of the extinct 
to the modern fauna of India, divest ourselves of the idea of peninsular India being con¬ 
nected by means of the Himalaya with Central Asia; rather we must look upon it as having 
been disconnected from the latter region by a deep Eo-Miocene sea, which deposited the 
extensive nummulit.ic formations of tire Himalaya a,nd Persia; and as having been con¬ 
nected by the old “ Indo-Oceania” with Africa, and so with Europe. Subsequently to the 
(at all events partial) upheaval of the nummulitie series and its overlying sandstones and 
red clays, the great fresh-water Mammaliferous series was deposited : and it becomes an 
interesting question to consider whether these were deposited previously or subsequently to 
the submergence of “Indo-Oceania.” 
Before there can he any chance of answering this question, the geological age of the 
Siwaliks must be certainly fixed; whether in fact they should he placed in the Miocene or 
Pliocene period. The number of extinct genera of Mammalia in these beds is so large, that 
on first thoughts one would be at once inclined to say that they cannot he of later age than 
Miocene: this view was taken by Dr. Falconer, and has beeu subsequently acquiesced iu by 
most other writers. In considering this question we must, however, bear in mind, that it 
does not at all follow that the same rule holds good in India as in Europe ; changes of climatal 
and physical conditions, and consequently of the forms of Lite, may have beeu infinitely more 
rapid in the one region than in the other. 
Besides the Mammalian remains, a considerable number of species of Molluscs have been 
collected from the Siwaliks; these were sent by Dr. Falconer to the late Prof. E. Forbes for 
determination ; a considerable number were identified with living forms, and Mr. Theobald 
now tells me that he believes (owing to the more complete collections ol living species now 
extant) neaily all are identical with living species. At the end ot his note on the subject 
(Pal. Mem., Vol. 1, p. 390) Prof. Forbes says that the Molluscan evidence tends to place the 
age of the Siwalik Fauna as not newer than older Pliocene; if, however, Mr. Theobald’s 
suggestion turn out to be correct, the age would, from the Molluscan evidence, be later than 
this. In the first volume of the Palaeontological Memoirs (p. 26) it is stated that in the 
opinion of a then eminent authority (Mr. Benson), nearly it uot quite ,all the Siwalik shells 
were identical with living species. Our collection of these shells in the Indian Museum is 
not at present very extensive ; if additional specimens be obtained, it would be very important 
to have the whole series carefully compared with their living congeners. 
There is, however, the still more important fact, that the Gharial of the Siwaliks, and 
one species of Crocodile, are absolutely indistinguishable from their living Indian represen¬ 
tatives, whilst there is, 1 believe, no instance of reptiles having survived from the Miocene 
to the present period. Both of the above facts to my mind point very strongly to the 
Pliocene age of the Siwaliks : Emys tectum is also another Siwalik lieptile which has 
survived down to the present time. 
Another very important piece of evidence tending to the same view is afforded by 
a statement of Mr. W. T. Blauford’s (Rec. Gaol. Surv. India, Vol. IX, pt. 1, p. 18) in his 
Geology of Sind ; it is there shown that the Manclihar beds, which he correlates with the 
Siwaliks (and from the few fossils brought from them, I should say that they cannot possibly 
be newer) rest uueonforwably on beds “ which axe at the oldest Upper Miocene.” If this 
identification is certain, it at once disposes of the Miocene theory of the age of the Siwaliks. 
The assemblage of Mammalian genera in the Siwaliks, and other Indian Tertiaries, 
is so incongruous, according to our ideas derived from the European fauna (as was long since 
pointed out by Dr. Falconer), that it seems to be impossible from this alone to decide 
their age. Forms such as Chalicotherium , Acerotherium and Dorvatherinm are very 
characteristic of the Miocene of Continental Europe ; but then we find mixed with them such 
