LOWEE CKETACEOUS. 583 



B-C 19-30. VENEZtTELA. 



As regards the Lower Cretaceous, Sievers ^^'* in describing the Cretaceous 

 rocks of Venezuela distinguishes conglomerate and breccia at the base, followed 

 by red sandstone, yellow and white quartzose sandstone, and limestone. From 

 the descriptions of these several formations, which consist chiefly of details of local 

 occurrences, the following notes may be taken: 



The clay slates which are assigned by Sievers to the Archean and which for the 

 sake of distinction have been placed by the present compiler in the metamorphic 

 Paleozoic are unconformably overlain in many places in the Cordillera by massive 

 deposits of conglomerate and breccia which Sievers calls the Lagunillas conglomer- 

 ates. They consist of fragments of the "Archean" rocks embedded in a clay and 

 sandy cement. Their horizontal extent is in places considerable; the thickness 

 in the vicinity of Lagunillas is stated at 700 meters. Sievers leaves one in doubt 

 as to whether the conglomerates should be assigned to the Cretaceous or not, saying : 



These conglomerates appear widely distributed throughout the Cordillera and always 

 occur between the Archean rocks and the succeeding red and yellow sandstones which we may 

 well regard as Lower Cretaceous. Sometimes they rest upon gneiss, as at Lagunillas, some- 

 times on clay slate, but they always constitute an intermediate member between the Archean 

 and the Cretaceous. One is obliged to regard them as a coastal formation developed around 

 islands of the older gneiss and clay slate which now constitute the core of the Cordillera. The 

 time at which these conglomerates were formed can not be determined with certainty, but they 

 must be older than the red and yellow sandstone which we regard as the lowest member of the 

 Cretaceous. It is therefore probable that they introduced this period. 



After citing the localities at which the Lagunillas conglomerate occurs, Sievers 

 continues : 



The conglomerate and breccia are followed by the Cretaceous series, to which most of the 

 sedimentary deposits of the Cordillera belong and which occupies a much greater area than 

 that of the Archean formations. The determination of the age of these formations depends 

 essentially on a few fossils from the blue limestone of Tachira and Barbacoas, which are mostly 

 ammonites and may be correlated with the Upper Albien of the Middle Cretaceous as deter- 

 mined by Prof. Steinmann. The strata which underlie these limestones are therefore older 

 Albien. There are red and yeUow standstones as well as the white sandstone. Unfortunately 

 they are as a whole very poor in fossils, but they may be considered as Cretaceous, as in litho- 

 logic character they are very similar to the corresponding Cretaceous deposits of Europe. * * * 



The red sandstone follows directly upon the deposits of the Lagunillas conglomerate. 

 It is mostly coarse and rich in mica, though also sometimes fine grained, usually according to 

 its relation to the conglomerate, whether directly deposited upon that formation or farther away 

 from it. * * * 



At many points in the Cordillera de Merida we observed a white to yellow coarse-grained 

 saccharoidal quartz sandstone which in many respects strongly reminds one of the Quader 

 sandstone of Saxony. * * * Although this sandstone resembles the Planer (of Germany) 

 and accordingly should be placed among the upper formations of the Cretaceous, it can not be 

 denied that it occurs in the Cordillera under the limestone which is determined as equivalent 

 to the Albien and outcrops together with the red sandstone. * * * The yellow sandstone 

 frequently grades into the red but in general is much more widely distributed than the red 

 sandstone. Where the red is entirely wanting ^that is to say, throughout the eastern portion 

 of the range — the white sandstone seems to replace it. 



