210 GEOLOGY OF PART OF CUBA. 
is sharply conchoidal; the texture is perfectly compact, and inclined to waxey. It burns 
into a superior quality of lime. In the absence of more appropriate names, we called 
these two hills, the Wild Dog hills, because they afforded secure retreats to the numerous 
wild dogs with which the country is infested. 
On the southern borders of Sabana Vieja, corresponding with the fourth limestone 
chain, appear two other conical hills, which seem to rise up from the midst of the sur- 
rounding Savana rock. The metamorphic influence is less observable than in those 
rocks which are near the anticlinal axis. Here the stratification of the white limestone 
is distinct and undisturbed, except so far as may be indicated by a flexuous or undu- 
lating arrangement of its beds. In the westernmost of these two hills the general dip of 
the stratification is fifty or sixty degrees, to the S. E. For the most part the beds are 
thin; some of them contain long, flattened, red, cherty nodules; or the mass is interspersed 
with seams of flesh-coloured calcareous rock, from two to eight inches thick. The east- 
ernmost hill also consists of thin wavey beds; which, along the crest of the ridge, dip as 
much as seventy-five or eighty degrees to the S. E. In this case, the limestone is mottled 
with reddish nodules, and interstratified with similarly coloured red seams. 
The colour of the Gibara limestones exhibits various gradations, from a pure white. 
These tints are always extremely delicate; and are cream-coloured, slightly greenish, 
yellowish, or even pink. In structure this marble is, for the most part, beautifully fine 
and compact :—too much so, it is said by architects, to admit of its adaptation to external 
building purposes. But for finished, delicate work, in the interior; and for the orna- 
mental departments of architecture and sculpture, it appears to be well adapted. 
Upon the flanks of most of these mountains, between the greenstone and our compact 
limestone, occur tufaceous deposites; derived, doubtless, from the latter, and brought 
down by numerous descending springs. This soft tufa invests various substances, and 
contains beautiful impressions of leaves and vegetable fragments. We have observed 
this, in particular, near the base of La Silla, and in the direction of Lilavason; where 
extensive marley tufaceous accumulations attest the disintegration of the neighbouring 
limestone. Often this tufa envelopes fragments of various rocks, and after consolidation, 
represents a variety of breccia. The streams of this country, particularly near the anti- 
clinal axis, abound in instances of such aggregations. These, however, must not be 
confounded with the tufa which is derived from the decomposition of the old coral rocks, 
near the coast: such, for instance, as that which, near Havana, is used, somewhat exten- 
sively, in the making of carbonic acid gas, for the manufactory of soda water. 
It is a very prevalent character of the Gibara limestone, that it contains or embraces 
large masses of carbonate of lime, of comparatively recent origin, enveloping shells. We 
account for this on the principle that they occupy in the solid form, what were formerly 
open fissures. This new rock is customarily of a reddish colour, generally quite fetid ' 
and encloses organic substances of which we shall speak hereafter. If the enclosing 
limestone ever contained organic remains, their forms have been obliterated by the 
changes of which we have such satisfactory evidence. The honeycombed irregularities 
of the surface, especially in the limestone of the First Chain, exhibit sharp projecting 
points, and innumerable round holes, an inch in diameter and two or three inches deep, 
resembling auger holes. 
