1902.] AND ANCIENT GEOGRAPHY. 32i* 



that Madagascar became separated from Africa in the Oligocene or 

 Miocene ; at the same time he connects Madagascar with India, and 

 believes that this connection was not severed before the beginning 

 of the Pliocene. In opposition to this we maintain that the 

 connection of Madagascar with India was interrupted before that 

 with Africa. 



As the only remnants of this old bridge, the Seychelles have been 

 preserved. They consist, according to Bauer, 1 chiefly of granitic 

 rocks, which are accompanied by dikes and sheets of volcanic 

 origin. Only traces of sedimentary rocks are found, and these 

 point to a very old age. While we thus may safely take the Sey- 

 chelles for a remnant of this old bridge — and this is confirmed by 

 the presence of the East- African genus Deckenia — the other islands 

 of the Indian Ocean (Chagos group, etc.), are coral-formation. 

 They may rest upon the highest peaks of the submerged Lemuria, 

 but the latter itself has disappeared here. Consequently the fauna 

 of these islands — at least as regards freshwater Decapods — does not 

 contain any forms indicating this old bridge, since they must have 

 all been drowned. 



The northeastern extremity of the Indo-Madagassian peninsula 

 was formed by the present peninsula of India. According to Neu- 

 mayr and Koken, this latter was separated, from the Jurassic to the 

 older Tertiary, from the rest of Asia, that is to say from the Sino- 

 Australian continent, by the Strait of Bengal, and, during the 

 older Tertiary, India was, according to Koken (/. c, p. 452), an 

 island (also disconnected from Madagascar). It seems, however, 

 that this separation of India from the rest of Asia was not so per. 

 manent as is believed by these authors. It is true, as regards its 

 tectonic configuration, India has nothing in common with Asia, 

 but it seems that there was a. connection, at least at certain periods. 



That the " Central Mediterranean Sea " of Neumayr extended 

 during the Jurassic period across northern India to the Bengal 

 Strait, separating India and Asia, seems to be correct, since no 

 evidence to the contrary has been brought forth, and the latest in- 

 vestigations have shown that Jurassic deposits are widely distrib- 

 uted not only in the western but also in the central Himalayas. 2 

 But during a part of the Cretaceous, this strait does not seem to 



1 Nenes Jahrb. f. Mineral., etc., 1898, Vol. 2. 



2 See Griesbach, Rec. Geol. Surv. India, 26, 1893, and Diener, Verh. k. k. 

 geolog. Reichsanst., 1895. 



