206 L. V. Dalton — Geology of Venezuela. 



Along the western flank of the Cordillera of Merida, in the northern 

 part of the Segovia Highlands, and throughout the Serrania Interior 

 to the Gulf of Paria, there are belts of vaiying extent of a series of 

 beds, mainly clays, with brown sandstone, carbonaceous shale, thin 

 limestone, clay ironstone and pyrites, etc., which furnish fossils 

 both of a high Cretaceous horizon and of Lower Tertiary age, the 

 Cretaceous fauna being confined to the lower beds, while IS^ummulites 

 and other Tertiary fossils are found in the higher strata. They are 

 well seen in the Cerro de Ore (so called from the abundance of 

 yellow pyrites, mistaken for gold) near E,ubio in Tachira. Dr. Sievers 

 tiierefore termed this group the Cerro de Oro Series (System). 

 The age of the beds included under this name appears to range from 

 Upper Senonian to Eocene, i.e. probably equivalent to other similar 

 deposits known as Cretaceous in Trinidad. 



The three geological divisions enumerated above would seem to be 

 separated from each other only by short intervals of time, or by none 

 at all, but there appeal's to be a greater difference in age between the 

 Cerro de Oro Group and the next later series, which is markedly 

 unconformable to all older rocks. 



On the east side of the Lake of Maracaibo, and possibly on the west 

 also, as well as on the Coro coast and over the peninsula of 

 Paraguana, in some of the islands on the Cumana coast, and under the 

 Llanos, there is a series of calcareous sandstones and shales, often 

 highly fossiliferous, which appear to correspond to the ' Newer 

 Parian ' of Trinidad. Fossils were collected from Cumana by Mr. Wall 

 and described by Mr. Guppy of Trinidad, between 1860 and 1870, 

 which show the age of the beds to be probably Upper Miocene, 

 so that our first scientific data in regard to them came from Cumana; 

 it seems fitting, therefore, to affix the name Cumatid Series. 



Finally, there are two groups of strata widely different in character, 

 but probably of the same age : one, the Llano Deposits (current- 

 bedded clays and gravels surmounted by gravels), covering the whole 

 of the great plains of Venezuela ; the other a series of shell-beds with 

 remains of mollusca little different from those now inhabiting the 

 Caribbean Sea. These occur all round the coast from Coro eastwards, 

 are well seen at Cabo Blanco, west of La Guaira, and form practicallj^ 

 the whole of the island of Cubagua, whence the name Cubagua Beds 

 is suggested for them. Both these groups may be taken to be of 

 Pleistocene age, and with them should be classed the gravel and 

 river deposits of the hills, with Megatherium and other mammalian 

 remains, found near Tocuyo, the lake of Valencia, Mount Turumiquiri, 

 and other points. 



The Recent Albwiiim, which covers so great an extent in the delta 

 and round the lake of Maracaibo, needs no special remark. 



Igneous rocks of the plutonic type also occur in Northern 

 Venezuela, and the outcrops are in some cases of wide extent ; thus, 

 the Sierra Nevada and other regions of maximum elevation in tlie 

 Venezuelan Andes are composed of a white granite, apparently of 

 more recent date than the metamorphosed strata surrounding it. The 

 same rock occurs under much of the peninsula of Paraguana, where 

 there is also an intrusion of augite-porphyry in the Cerro de Santa 



