1902.] AND ANCIENT GEOGRAPHY. 343 



indicate that this whole region, i.e., Central America, the Greater 

 Antilles and the northern coast of South America, possesses an 

 **old basement of granitic rocks of earlier age than the oldest 

 determinable sedimentary rocks" (Hill, 1898, p. 241), which, in 

 its west-easterly strike, differs entirely from the present mountain 

 ranges of North and South America, and it is possible that these 

 parts once formed a unit, a solid continental mass. As to tiie age 

 of this continent we may form an idea if we consider that (Hill, 

 /. c, p. 243) Jurassic beds are absent in this region, so that during 

 this time at least this continent was in existence. The same seems 

 to be true for a large part of the Cretaceous time. Cretaceous 

 deposits are wanting in Central America from Costa Rica eastward 

 in the Isthmian region an^ on the West Indian islands.' On the 

 other hand, Cretaceous beds are found in Guatemala to the north 

 of the old granitic mountains. They are also extensively developed 

 to the south and southeast of the old granites in Colombia and 

 Venezuela (see below), and thus it seems that this old continent 

 was washed to the north as well as to the south by Cretaceous seas. 

 But at about this time (toward the end of the Cretaceous) tids 

 old Mesozoic Antillean continent must have been destroyed, prob- 

 ably by the formation of the Caribbean Sea. We do not know 

 much about the exact time when this happened, but we know that 

 the subsidence forming this basin within this old mass was accom- 

 panied by a faulting along the margins of the subsiding area. This 

 fault is cle.irly seen at the coast ot Venezuela, where, according to 

 Suess (1885, p. 687 f.), the old coast range breaks off to the north. 

 The fact that within the whole region of the Caribbean Sea no 

 Cretaceous deposits are positively known makes it very probable 

 that the formation of this depression falls at the end of the Meso- 

 zoic age.^ 



1 There are, however, Pre-Tertiary sediments, belonging possibly to the upper- 

 most Cretaceous, in some of ihe Greater Antilles (see Hill, Amer. Journ. Sct.j 

 Vol. 48, 1894, p. 197) ; but this again demonstrates that sedimeniauon in these 

 parts did not begin till the very end of the Mesozoic time, 



2 There are Cietaceous deposits of Lower Senonian age in western Venezuela 

 which po>sess the Mediterranean type (see Gerhardt, m A^. Jahrb. Mineral. , 

 etc., Beil., Bd. 11, 1897, p. 87). This possibly is the first indication ot the exist- 

 ence of the Caribbean Sea. But we must not forget that the Lower Cretaceous 

 of Colombia and Peru also exhibits Mediterranean character, which is due, no 

 doubt, to the Orinoco connection. It is remarkable that the relation of these 

 Lower Cretaceous beds to Texas is not very evident, they probably being sepa- 



