250 BULLETIN OF THE 
the steeper bluffs are thickly coated with“ tepetate,” or tufaceous deposits. 
Great caverns abound in these rocks in many parts of the island. 
These limestones have been so greatly altered since their original 
deposition that, from macroscopic examination, it is difficult to tell their 
original character or the conditions under which they were deposited. 
They certainly do not anywhere exhibit the enormous proportions or 
abundance of coral remains so apparent in the reef rock, ner do they 
show, except occasionally, an abundance of casts and moulds of molluscan 
shells, and I seriously doubt whether, as alleged by Crosby? and Kimball,? 
and formerly by A. Agassiz,’ they are coralline in origin, as in the modern 
reef rock. ‘They sometimes contain traces of coral, but I do not think this 
proves that they were reef rock, for all corals are not reef building, and 
the organic remains are far more abundantly molluscan than coralline. 
Neither can they be called chalks, although very foraminiferous in places, 
for they are too coarsely crystalline, clastic, and molluscan, and lacking 
in that fineness and uniformity of texture seen in the chalky limestones, 
which I have had considerable experience in studying. In places at their 
basal contact they are certainly detrital, showing (as at the reservoir 
south of Havana, where they are in contact with the older series of clays 
and serpentines) a distinct conglomeratic structure, and being composed 
largely of shell fragments and beach wash. Near Villa Clara they contain 
very small fragments of igneous material derived from the older rocks 
which they buried. In many places they are distinctly sedimentary, as 
seen in the Castillo Principe Plateau west of Havana, where they con- 
tain alternations of stratified, slightly yellow argillaceous layers, while 
the several hundred feet exposed in the cafion of the Rio Armendaris, 
south of Havana, exhibit far more molluscan remains than coral, although 
some corals are present. Likewise at Matanzas the older limestones ex- 
hibit every character of sedimentaries with molluscan remains, rather 
than coral reef structure. At Baracoa, Nuevitas, and elsewhere on the 
west coast, the limestones not only appear to be sedimentary, but they 
alternate with beds of a yellow argillaceous and arenaceous material, 
clearly sedimentary, and containing great numbers of molluscan fossils. 
In fact, I do not believe that any of the limestones below No. 2 of the 
Matanzas section (Plate II. Fig. 4) are of reef rock origin, but am of 
the opinion that they are mostly organically and chemically derived sedi- 
1 On the Elevated Coral Reefs of Cuba. Proceedings of the Boston Society of 
Natural History, Vol. XXII. pp. 124-129. 
2 American Journal of Science, December, 1884. 
3 Bull. Mus. Comp. Zool., Vol. XX VI. No. 1, December, 1894. 
eo 
