MUSEUM OF COMPARATIVE ZOOLOGY. 249 



marly or very slightly siliceo-argillaceous beds. The limestone beds 

 have beeu well described lithologically by Sagra, as follows : — 



" It is white in color, or light yellow, with a fracture sometimes smooth, 

 sometimes conchoiJul, containing some concretions, — very often casts with 

 petrifactions. The fossil substances enclosed in the limestones are very abun- 

 dant. . . . The porous beds of the middle part of this locality, as near Batabano, 

 resemble those spongy and calcareous banks of the Jurassic of Francone, near 

 Dondorf, Pegnitz, and Tumbach. These yellow cavernous beds, which show 

 cavities from four to five inches in diameter, alternate with others entirely com- 

 pact and less charged with petrifactions. The line of hills which border the 

 valley of Los Guiues toward the north, and which unite the hills of Camoa 

 and the Tetas de ]\Ianagua are of this last variety, the color of which is a rosy 

 white, sometimes almost lithographic, like the Jurassic limestone of Pappenheim. 

 The compact and cavernous beds contain small ferruginous masses, and are the 

 same formation that Humboldt designated the Calcarie de los Guines, which is 

 exposed on the southeast near Trinidad, on the hills of San Juan, already 

 referred to, and on the north coast, near Matanzas. In these different localities 

 it exhibits grand subterranean cavities, wdiere rain water accumulates, and in 

 which many considerable streams submerge." ^ 



I miglit add to this description the remark that these rocks bear a 

 striking lithologic and structural resemblance to the Neocomiau and 

 Middle Cretaceous rocks of Texas. 



Although distinctly stratified, the limestone is irregular in texture. 

 While it is, in general, of a cellular structure, a cubic foot of it in any 

 locality exhibits great irregularities in hardness and compactness. There 

 are spots so hard and crystalline that it is difficult to break them with 

 a hammer ; other spots are firmly crystalline and banded ; still others 

 are rounded indurations ; and again there are soft, pulverulent spots. 

 All of this irregularity of texture is secondary, or in a condition of 

 alteration produced by aqueous solution. In some places the cellular 

 cavities are many feet deep, while the remaining portions are indurated 

 into sharp edges of coarse, sometimes crystalline limestone. So com- 

 pletel}' has the work of solution and intei'stitial change gone on that it 

 is doubtful whether the ori!j,inal nature of the rock is anvwhere well 

 preserved. 



This weathering and induration is very similar to that which I have 

 often noticed in the chalky Lower Cretaceous limestones of Texas. On 

 the resisting summit points the rock is hardened and worn into the 

 peculiar Liliputian ridges known in the Alps as " Karrenfelder," while 



^ Histoire Physique de Cuba, Tom. L p. 109. 



