254 BULLETIN OF THE 



frequently tilted at an angle of forty-five degrees, as at Baracoa, and 

 sometimes intensely folded into anticlines, as back of Havana, and pre- 

 sents every degree of folding and disturbance in the numerous railway 

 cuts between Havana and Matanzas, at Villa Clara, Yumuri, and else- 

 where. In fact, it is seldom if ever subhorizontal on the north coast, 

 and the later deposits are entirely unconformable with it. While the 

 details of this disturbance could not be wrought out during the brief 

 time which I spent upon the island, its character can be seen in the 

 various sections and illustrations given on Plate I. 



The general lay of the old limestone is that of a low anticline whose 

 axis corresponds with that of the island, with folds more greatly devel- 

 oped along the northern coast. This folding took place clearly near the 

 close of Tertiary time, and prior to the deposition of the Post-Tertiary 

 formations and elevations to be described, and indicates one of tlie most 

 important epochs in the geological history of Cuba, representing, as it 

 does, an orogenic folding not elsewhere traceable in North American 

 history. This folded condition of the limestone, however, has in no 

 manner influenced the later topographic detail of the surface, and was 

 mostly, if not entirely, antecedent to the great regional elevations to be 

 described later. 



The Post-Tertiary Formations. — In strong contrast to the older Ter- 

 tiary limestones is a more modern group of limestones of undoubted 

 coral-reef origin, which border the coast in most places, or form small 

 coral islets adjacent thereto, and are locally known as soboruco. 



M. Ramon de la Sa!2:ra has defined this formation as follows : — 



" L'autre forni.ition de calcaire modenie, qui a recu dans le pays le noin de 

 sohnruco, se tronve de long de la cote dans plusieurs endroits de I'ile ; elle est 

 tellement recent, que son agglomeration continue menie aiijourd'hui, et c'est 

 a elle que I'on doit les cayes, les recifs et tons les bas-fonds de coraux. Les 

 parties superieures s'elevent parfnis a partir d'une profondeur de vingt a trente 

 brasses. Toutes les inegalites de cette roche sent recouvertes d'une couche 

 calcaire agglouieree avec des restes d'animaux, des coquilles, de coraux, et de 

 madrepores." i 



The elevated reef rock can always be recognized by the perfection and 

 abundance of well preserved remains of reef-making corals, which form 

 the greater proportion of the mass and unmistakably show its origin, and 

 by the absence of subdivisions into lamination and bedding planes. The 

 surface is practically the old level of the submerged reef, the sharper 



1 Histoire Physii^ue, etc; de I'lle de Cuba, Tom. I. p. 110. 



