260 BULLETIN OF THE 
has assumed the aspect of an ancient and much carved land surface, 
while the geology, on the other hand, tells us that it is comparatively 
new. The peculiar surface configuration of the island is solely due to 
the decay and erosion of these older limestones. Where they predomi- 
nate, the interior country remote from the somewhat abrupt coast is 
marked by extensive flats or Llanuras, upon which rest, without any 
apparent systematic arrangement, short ranges of abrupt hills-or knobs. 
Both the plains and the mountains are composed of the same old 
limestone. (Plate III.) 
Although the rocks dip at various angles in gentle waves or folds, and 
in some cases with numerous short anticlines, it was impossible to make 
out any system of disturbance which influenced the minor topography. 
This sub-arrangement of the underlying limestone structure does not 
influence the present surface topography, as the strata are of insuffi- 
cient induration to create topographic irregularities. 
The limestones decay so rapidly at the surface that they can seldom 
be seen in a freshly exposed condition except in railway cuts and quar- 
ries. Everywhere they disintegrate into a rich red residual soil, some- 
-times of great depth, which contains a large percentage of iron derived 
from the limestone. This sub-aerial decay is beautifully shown in the 
cuts of the Havana and Matanzas railway near the latter city, an illus- 
tration of which is shown on Plate I. Fig. 7. This iron has great 
economic value in the vicinity of Santiago de Cuba, under the conditions 
shown by Kimball. The limestone is also melting away by deep un- 
derground solution, and is very cavernous. This decay, proceeding 
irregularly, being much greater in some spots than in others, produces 
large sinks, as in the limestone regions of Kentucky, only of a vastly 
greater area. Thus it is evident that the deep, sloping indentations 
are produced not solely by surface corrosion, but partly by underground 
decay, the streams carrying away the lime in solution, rather than as 
physical débris. A most remarkable illustration of the effect of solution 
upon the topography is the valley of the Yumuri de Matanzas, a plan of 
which is shown on Plate II. Fig. 9. 
When this rapid disintegration and degradation of the old limestone 
is considered, it is evident that the ancient limestone summit of the 
island must necessarily have been greatly lowered in outline. In other 
words, the present highest levels of the limestones do not represent the 
altitudes which they formerly attained, but are merely planed off rem- 
nants. It is impossible to determine how great a portion of the top of 
Cuba has been thus removed, except so far as to say that, judging from 
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