268 



formations of llie Soulli-east of tlie United Slates. Now, in the 

 Habana rocks, described above, large Lepidocjclinae are absolutely 

 lacking; tliej contain only dwarf-species which — as experience 

 in Asia and Europe has taught us — are more or less indicative 

 of younger formations, so that part of the "Older Habanaformation" 

 must very likely still be referred to the Oligocene. And this is not 

 all. In the city of Habana and west of it the Older Habanaformation 

 is overlain by rocks of quite similar petrographic habitus, but they 

 are much less disturbed. These rocks of the „Younger Habana- 

 formation" (organogenetic limestones, white and yellow marls, sub- 

 marine tuffs) form namely a monocline, whose core still exhibits 

 steep dips — up to 40° and higher — . The younger portions of this 

 formation, however, which in its totality is dipping towards the 

 sea, are much less steep. In the suburb of Vedado the marls of 

 this formation are overlain by coral-limestones which are also dipping 

 down towards the sea. The rocks of this "Younger Habanaformation", 

 which are so beautifully exposed in the marlpits of Puentes Grandes 

 and of Cienaga and at the Castillo del Principe, are lying uncon- 

 forniably — as the accompanying map indicates — on the rocks 

 of the "Older Habanaformation": while the strike of the older rocks 

 jg E. — W., that of the younger is about N.E. — N.N.E. The facts, 

 however, that in the deeper parts of the younger formation the 

 layers are very sharply iïïclined, and that there is a remarkable petro- 

 graphic similarity between the two formations tend to show that 

 the stratigraphical gaping between the two formations is only very 

 inconsiderable ; nay, in all probability, the unconformity is only 

 "tectonic", is originated during the folding, and the two formations 

 succeed each other most likely without a significant stratigra- 

 phical gap. 



Now, M. Sanchkz RoiG^) has for several years been collecting fossils 

 from the marlpits of Cienaga. It is especially the teeth of Selachii 

 that were encountered here. They point to a miocene age, while 

 the more southern limestones of Vedado belong even to the Pliocene. 



The foregoing no doubt justifies the conclusion that the rocks of 

 the "Older Habaria formation" belong partly to the eocene, partly 

 to the oligocene, that the tertiary orogenetic movements in this part 

 of Cuba began towards the close of the Oligocene, and that they 

 continued even in the Pliocene. 



So while in the North the layers of the "Older Habanaformation" 

 are overlain unconformably by miopliocene rocks, which have still 



1) M. Sanchez Roig, Boletin de Minas, Habana, N». 6, ]920. 



