TERTIARY HISTORY OF THE CIENFUEGOS REGION. 79 



SO as to form the plain reaching to the interior of the island. Along the 

 railway and along the river the strata are exposed and show variable 

 inclinations up to 60° or 70° in a direction south 30° west, and in one 

 place the beds are vertical. Lying upon this floor there were enough 

 patches of Matanzas marl to show that the pre-Matanzas erosion was ver}^ 

 extensive, and even this later marl has been mostly removed by later 

 denudation. 



. Clenfiiegos region, — Cienfuegos is situated on a plain rising toward the 

 interior of the island, but in the intervening region the country is un- 

 dulating. The underlying materials are composed of soft yellow marls 

 and incoherent sandstones. The beds dip from 20° to 30° southward. 

 The sandstones occasionally form a conglomerate 20 or 30 feet in thick- 

 ness. Of this section Mr G. F. Mathew says : 



*' The geological formation to which the yellow and buff-colored beds underly- 

 ing Cienfuegos belong appears to be one of great thickness. I have traced it in a 

 northernly direction as far as Caunau, four miles from Cienfuegos, and I did not 

 then reach its limit. This was in a line nearly at right angles to the strike of the 

 beds, and the intervening strata where exposed appear to have a regular dip. The 

 middle of the series consists of beds finer, more clayey and apparently more cal- 

 careous than those in the two places named [elsewhere]. At Caunau the strata 

 are quite firm and compact, becoming a coarse sandstone. For a mile or two back 

 of Cienfuegos there are numerous fossiliferous layers in the more clayey parts of 

 the series, from which I obtained the following forms : Belanus sp. ; Dentalum (?), 

 Ostrea, seven species ; Aiwnia sp. ; Pecten, five species ; Echinoids, of two species 

 (one a Scutelloid form) ; also a large Orbitoides, a shark's tooth, and parts of the test 

 of a crab, including the claws and carapace. Mr J. Lechraere Guppy, of Trinidad, 

 West Indies, who has kindly examined these fossils, says they are probably of 

 Miocene age. The formation in which they occur is evidently one of great magni- 

 tude and importance. ... I should think it is a mile in thickness where I 

 crossed it. It is probably limited by the Trinidad mountains to the east, and does 

 not appear on the lower part of the Damuji, where the older series comes to the 

 surface." 



This estimate of the great thickness may in part arise from concealed 

 faults, as the section is very much covered by soils, etcetera. Moreover, 

 it would appear that the Eocene equivalents are included in the esti- 

 mated thickness. The unusual mechanical character of these accumula- 

 tions is explained by their occurrence near the base of the Trinidad 

 mountains, which is the oldest land mass in Central Cuba, and the ad- 

 jacent extensive deposits of Cretaceous sands. 



Trinidad region. — In front of the Trinidad mountains, and extending 

 thence for a distance of 15 or 20 miles eastward of the cit}^ of Trinidad, 

 there is a ridge of coastal mountains consisting of a succession of peaks 

 arranged in echelon (see figure 5), and these separate Trinidad valley 

 from the sea. The peaks rise 600 to 700 feet above tide, with the inter- 



