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, sliort ranges of abrupt hills or knobs. 

 Botli 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 sul>aerial decay is beautifully shown in the 

 cuts of the Havana and Matanzas railway near the latter citj', an illus- 

 tration of which is shown on Plate I. Fig. 7. This iron has great 

 economic value in the vicinit}' 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 deca}', 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 1)\' underground 

 decay, the streams carrying away tlie lime in solution, ratlioi- than as 

 physical debris. 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 tlie 

 altitudes wdiich 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 



