68 J. W. SPEXCER — GEOGRAPHICAL EVOLUTION OF CUBA. 



Page 



Harbors 90 



Yumuri rock-basin 91 



Caverns 93 



Summary 93 



Introduction. 



In Cuba there are mountains higher than any on the eastern side of 

 North America ; extensive plains as level as those of the Atlantic coast ; 

 valleys formed at the baselevel of erosion, and deep canyons carved out 

 by the youngest streams ; the remains of enormous beds of limestones 

 mostly swept off the country, and coral reefs and mangrove islands ex- 

 tending the coastal ])lains into the sea; sea-cliffs, caves and terraces of 

 great and little elevation ; drowned valleys deeper than the fiords of 

 Norway indenting the margin of the insular mass ; caverns innumerable 

 and rivers flowing underground ; rifts through mountain ridges and 

 rock-basins; tilted, bent and overturned strata, dislocated and faulted in 

 modern times, so as to make youthful mountain ranges ; metamorphic 

 rocks and rocks igneous, and these again altered to secondary products ; 

 old baselevel plains or these modified and reaching across the island, 

 having insular ridges of older formations rising out of them, and with 

 the surfaces scarcely incised by the streams ; residual soils from the de- 

 com|)Osition of the rocks and sea-made loams and gravels ; in short, so 

 rapidly are the geologic forces working that one can see a greater variety 

 of structure and learn more of dynamic geology in Cuba than on more 

 than half of the temperate continent. 



Owing to the apparent connection of the Antillean region with the 

 American continent in recent geologic times, the writer visited Cuba in 

 order to ascertain the relationship of the atmospheric degradation of that 

 region to the later geologic formations. In his studies almost the only 

 assistance received was found in the difficultl}^ obtainable geological maj) 

 of Cuba by De Castro and Salterain y Ligarra, published in Madrid in 

 18S1, "Apuntes i)ara una Descripcion Fisico-Geologica de las Jurisdic- 

 ciones de la Hal^ana y Guanabacoa," by Salterain, Madrid, 1880; and 

 " Impressions of Cuba,'- by G. F. Mathew.* This last classic paper re- 

 lates to the region of Cienfuegos. A few other scattered notices will be 

 referred to in the text. 



General Topography. 



Cuba is 750 miles long and from 25 to 120 miles wide. In the western 

 part of the island there are ridges of mountains which culminate in a 



♦Canadian Naturalist, vol. vii, 1872, p. 19. 



