NATURAL AREAS AND REGIONS 



683 



nevertheless, following the report pub- 

 lished in 1901 by Hayes, Vaughan and 

 Spencer, and modifying it after the 

 recent discoveries, we may say that 

 the paleozoic formation is said to exist 

 in Mantua, at the western end of Pinar 

 del Rio province, where quartzite and 

 nearly black clay-slate are found. The 

 same formation is seen in Southern 

 Santa Clara province, in Sierra de 

 Cumanayagua and also in Northern 

 Oriente. During the Paleozoic ages, 

 intrusions of igneous rocks (serpentine, 

 granite, etc.) are supposed to have 

 occurred in sediments now disappeared 

 by erosion. 



Of triassic age seems to be the forma- 

 tion of two parallel series of sandstone 

 "Lomas" or rounded hills, north and 

 south of the Jurassic chain, between 

 Guane and San Diego de los Banos. 



The Jurassic was given as "absent?" 

 in the report referred to above, but its 

 presence has been proved by the dis- 

 covery of many Ammonites by Vesa, 

 C. de la Torre and later by M. Sanchez 

 Roig, near Vinales, in the chain of dark 

 blue hard limestone which forms the 

 axis of the Organos Range, in Pinar del 

 Rio. A great uplift and erosion must 

 have occurred during that period. 



Grey hard limestone of the Cretaceous 

 has been found in all the provinces, 

 with fossils of Radiolites, Barrettia, 

 Requienia, etc. Then occurred a sink- 

 ing of a large part of the Island. 



Sandstone probably of the eocene has 

 been observed south of San Diego de los 

 Banos, in Pinar del Rio. Then, ap- 

 parently, a large part of the Island was 

 submersed, or at least in Oriente, where 

 fossils of the Eocene have been col- 

 lected. Volcanic activities of that time 

 caused the formation of alternate 

 beds of volcanic rocks and Eocene 

 sediments. i 



Radiolarian ground of the Inferior 

 oligocene has been found near Baracoa 

 (Oriente). 



Limestone and marls of the Superior 

 oligocene are the most extensive geologic 

 formations of the Island, and occur from 

 Pinar del Rio to Oriente. Then the 



Island was all submersed, except some 

 peaks or ridges of North and South 

 Oriente, probably of Southern Santa 

 Clara, and surely of Pinar del Rio, 

 otherwise it would be impossible to 

 explain the actual presence in Western 

 Cuba of the old Microcycas calocoma. 



The miocene and the pliocene forma- 

 tions, given as absent or doubtful in 

 1901, has been proved to exist, by the 

 discovery of many fossils, in white 

 limestone, near Havana, by Mario 

 Sanchez Roig: Clypeaster lanceolatus, 

 Hemispatagus Hoffmani, etc., teeth of 

 Charcharodon megalodon, Lemna ele- 

 gans, and of other species of sharks. 

 A general uplift of the Island occurred 

 during the Miocene, followed by a slight 

 sinking and a nearly equal uprising at 

 the beginning of the Pleistocene. 



Quaternary formations are rather 

 extensive. Of the post pliocene seems 

 to be the clay -marl bed between Havana 

 and Matanzas. Not far from the last 

 locality have been found five tusks of 

 Hippopotamus. 



Pleistocene is represented by a very 

 jaggy limestone, containing recent spe- 

 cies, and surrounding most of the coasts, 

 especially the northern one. Then 

 Cuba was united with Isle of Pines. 



Of modern times are the alluvions of 

 some plains, as that of Pinar del Rio, 

 where is common an iron-oxid more or 

 less hydrated. Modern formations oc- 

 curred also between Cardenas and Sagua 

 la Grande, in the Camaguey plain and 

 in Oriente. 



Though much work remains to be done 

 in the study and comparison of the 

 faunas and floras of each of the West 

 Indian Islands and of the neighboring 

 continents, something may be said 

 about the geologic relations of Cuba 

 with the adjacent countries. 



According to Dr. Ekman, the Flora 

 of Cuba has enough elements in common 

 with Yucatan and Honduras to assume 

 that, probably in Precretaceous ages, 

 it was united with them. With Yucatan 

 through its western end, and with 

 Honduras either through Sierra Maestra 

 and Cayman Islands or indirectly 



