ZAPATA FORMATION. 85 



is taken from the extensive low peninsula west of Cienfuegos, which is 

 more or less covered by these mechanical accumulations. The best sec- 

 tions, however, were seen near Trinidad, which may be taken as examples. 



The Zapata gravels are water-worn and composed of quartz pebbles 

 from one to two inches in diameter, and in proximity to the Trinidad 

 mountains there are also limestone pebbles associated with the quartz. 

 The thickness of the beds are as much as eight or ten feet, and this de 

 posit is surmounted by red loams varying from one to ten feet in thick- 

 ness. The loams sometimes predominate and form one undivided bed. 

 In other places laminations of gravel occur in them. Occasionally the 

 whole formation is reduced to a few feet in thickness, but where filling 

 older erosion hollows it may greatly exceed the normal 15 or 20 feet. 

 Where the gravel is not apparent it is often difficult to distinguish the 

 loams from the red and similar appearing soils resulting from the solution 

 of the calcareous matter out of the Tertiary limestones. The formation 

 so closely resembles the Columbia of the southern coastal plains, described 

 by Mr W J McGee,* that their origin is apparently similar. The loams 

 are derived from the residual soils produced by the decomposition of the 

 Tertiary limestones, and most of the gravels are those obtained from the 

 remains of the Miocene formation. The loams are very rich in pellets of 

 iron oxides. 



Over the Zapata peninsula the formation is widespread, but owing to 

 the absence of deep ravines the sections are not seen as well as on the 

 higher land near Trinidad, where it occurs up to an elevation of 240 feet. 



The Zapata formation rests upon the greatly eroded surfaces of the 

 Matanzas and other earlier formations. Thus it closes the old Xagua bay 

 outlet, to be described later. To this formation apparently belong the 

 sands and gravels up to 10 or 15 feet above the Damuji river entering the 

 Xagua bay. From them Mr Mathew collected the following fossils, all 

 of which are living species : 



Murex brevifrons. Modulus lenticularis. Mytilus sp. 



Stromhus gigas. Cerilhenum versicolor. Venus cancellata. 



Strombus pugilis. Ceriiherium vulgatum. Lucina costata. 



Pyrula melongena. Bulla striata. Lucina tigrina. 



Nerita texsallata. Ostrea sp. Lucina jamaicensis. 



Neritinea virginea. Perna obliqua. Asaphis rugosa. 



West of Abreus, and also on the road to Caunau. the soils derived 

 from the Zapata series were found to contain a few fossils of living species. 



In the vicinity of Yaguaramas the Zapata peninsula has an elevation 

 of about 100 feet above the sea, and much of the poor surface soil consists 



*The Lafayette Formation : Twelfth Annual Report U. S. Geological Survey, 1892, pp. 347-521. 



