1902.] AND ANCIENT GEOGRAPIIY. 357 



from Guatemala to Venezuela is also emphasized by Hill (1898, p. 

 239 ff.), and he also thinks that, during Mesozoic times, a continu- 

 ous continental mass may have existed here, which reached as far 

 as Trinidad. We have seen above that the destruction of this con- 

 tinent was probably due, in the first place, to the formation of the 

 Caribbean depression, at the end of the Cretaceous. This also 

 agrees with Hill's view (1898, p. 260 f.) that during the whole of 

 the Cretaceous, or at least during the larger part of it, the Atlantic 

 and the Pacific Oceans were separated in the region of Central 

 America — that is to say, that there was a land connection between 

 the northern parts of Central America and northern South America. 

 But, according to Hill, this connection is not identical with the 

 present isthmian region, but was situated chiefly to the west of it. 



We have nothing to say against a western extension of this 

 Cretaceous land (which probably extended as far as the Galapagos 

 Islands), but we believe that the isthmian region and the present 

 Caribbean Sea also were land during this time ; the main point is, 

 that there was a connection between Guatemala, Honduras, Nica- 

 ragua, and the Greater Antilles on the one side, and northern 

 Venezuela on the other. 



These conditions changed considerably during the Tertiary. 

 First, the Caribbean Sea was formed, and possibly it extended 

 farther to the west and southwest than it does now. At least, parts 

 of the present land-bridge, the Isthmus of Panama, were covered 

 entirely by sea in the earlier Tertiary, and that this sea reached 

 from the present Caribbean Sea across to the Pacific is beyond doubt. 

 In the first line, the part through which the Panama canal is to be 

 built is composed entirely of deposits that are not older than 

 Eocene and Oligocene (Hill, 1898, p. 236), and this well agrees 

 with the investigations of Douville/ and Bertrand and Zurcher :* the 

 Old Tertiary sea (Eocene and Oligocene) must have here extended 

 entirely across the isthmus, from the Atlantic to the Pacific. 



The same seems to be true for the Nicaragua canal. According 

 to Hayes,^ there are no rocks along this route that are older than 

 Tertiary, and the Tertiary deposits probably belong to the Eocene 

 and Oligocene. The remarkable discovery has been made that 



1 C. R. Soc. geolog. France, 1898. 



2 Bertrand, M. et Zurcher, O. Etude geologique sur V hthme de Panama, 1S99. 



3 Hayes, C. W., " Physiography and Geology of Region Adjacent to the Nic- 

 aragua Canal Route " {Bull. Geol. Soc. America, Vol, 10, 1899). 



