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Presently we shall see that other facts also corroborate this hypothesis. 



In the vicinity of Habana a deeply weathered serpentine-massif 

 (see sketchmap) has long (Salterain 1. c. and others) been known. 

 In two localities — south of Gnanabacoa and due south of the bay of 

 Habana — quaitzainphibole diorites are found as a dyke. These 

 moderately acidic plagioclase rocks forcibly reminded me of the 

 granular crystalline rocks of the "Pacific type", described by Högbom (Ic.) 

 and derived from the Virgin Isles. The felspars of this quartz- 

 amphibolediorite all had a refractive index higher than canada 

 balsam, but the refractive index of most of them was lower than 

 that of quartz, to which they often are contiguous in the micro- 

 scopical sections. Consequently they belong to the acid portions of 

 the plagioclase series. Indeed the fact that this rock is poor in 

 potassium and comparatively rich in silicic acid (much quartz and 

 many acidic plagioclases) reminds us forcibly of many "Andes-rocks". 

 Also by the occurrence of granular rocks of this type Cuba is united 

 to the American continent on the one side and on the other to the 

 Virgin Isles. 



When perusing the literature concerning the Antilles we are 

 impressed with an other incongruity between Cuba and the other 

 Antilles. Already long ago young Radiolaria-bearing deposits became 

 known in Barbados (Harrison and Jukes Brown, 1. c.) which many 

 geologists regard as true deepsea-deposits. R. T. Hill also described 

 tertiary Radiolaria-deposits in the east of Cuba (Baracoa). However, 

 whereas in Barbados the Radiolaria deposits overlie unconformably 

 the older tertiary — which developed there as a terrigenic deposit — 

 and have only been subject there to faulting and not to folding, 

 the Radiolaria deposits of Baracoa have a steep dip, so that there 

 seemed to exist a stratigraphical incongruity between these deposits 

 in the two islands. In the neighbourhood of Habana I encountered 

 Radiolaria-bearing rocks in two levels of the Tertiary. In the first, 

 place white marls in the "Older Habanaformation" near CerrOi 

 with a dip of 75° southward. They are entirely filled up with 

 Radiolaria that belong for the major part to the Spumellaria, for 

 a small part however also to the Nasselaria (fig. 1). Secondly, in 

 the most recent part of the "Younger Habanaformation", i. a. in 

 the marlpits of La Cienaga, white Globigerina marls occur which 

 contain a not inconsiderable amount of Radiolaria. Now it is very 

 well possible that the Radiolaria-marls of Cerro are the equivalent 

 of those of Baracoa in East-Cuba, whereas the Radiolaria-bearing 

 Globigerina marls of La Cienaga are stratigraphically more like the 

 deposits in Barbados. Also the contrast which apparently exists in 



