19S B. T. Hill — Tertiary and later 



1 could find no fossil remains except one poorly preserved 

 plant impression, a monocotyledon, which, with the general 

 character of the material gave the impression that these clays 

 were deposited when the conditions of sedimentation were far 

 different from those of the present. I cannot say positively 

 that the Esperanza clays are identical with the clays at Havana, 

 but they both occupy the same relative position between the 

 limestones and the metamorphic formation, and are both ex- 

 posed by the erosion of the overlying limestone. De Castro 

 refers the clays of Esperanza to the Cretaceous period ; upon 

 what ground except stratigraphic position, I cannot say. He 

 reports other Mesozoic sedimentaries at both ends of the Island 

 together with Ammonites and Radiolites which would clearly 

 indicate the occurrence of Cretaceous deposits in Cuba, but I 

 had not time to study these. 



The White Limestone Formations. — In strong contrast with 

 the Esperanza clays and the older metamorphic floor are the 

 Tertiary and later limestones which cover them, and which are 

 the predominant geologic feature of Cuba. 



The study and classification of the limestone group is diffi- 

 cult owing to the folding, induration, erosion, the thick cover- 

 ing, in places, of soil and vegetation, the universal alteration 

 they have undergone through solution and internal changes, 

 and the general concealment by tufaceous incrustations of well 

 defined stratification planes and partings. They are clearly 

 divisible into two general groups — the older and the newer. 

 The latter consist mostly of unfolded rocks of undoubted 

 coral-reef origin, and occur on the lower levels adjacent to the 

 coast, while the former, if of coral-reef origin, have lost all 

 characteristic proof of such origin, are undulated and folded 

 and constitute the uplands and high coastal scarps against and 

 around which the later coral rock was deposited. 



The Older Limestones. — The more ancient limestones and 

 accompanying beds constitute all the limestones of the Island 

 seen by me above an altitude of 100 feet. They are very 

 diverse in texture and composition. "Where good exposures 

 are obtainable they usually exhibit well defined stratification 

 and separation planes, never seen in the undoubted reef rock, 

 sometimes alternating with more marly or very slightly arena- 

 ceous layers. While it is in general cellular, a cubic foot of it 

 in any locality exhibits great irregularity in hardness and com- 

 pactness. There are spots so hard and crystalline that it is 

 difficult to break them with a hammer ; other portions are 

 firmly crystalline and banded ; while again there are soft, 

 pulverulent layers. All of this difference in structure is of 

 secondary origin, the result of alteration. In some places the 

 cellular cavities are many feet deep, often extensively cavern- 



