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 the 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 Sagra has defined this formation as follows : — 
“autre formation de calcaire moderne, qui a recu dans le pays le nom de 
soboruco, se trouve de long de la céte dans plusieurs endroits de Vile; elle est 
tellement récent, que son agglomération continue méme aujourd’hui, et c’est 
a elle que l’on doit les cayes, les récifs et tous les bas-fonds de coraux. Les 
parties supérieures s’élévent parfois 4 partir d’une profondeur de vingt a trente 
brasses. Toutes les inégalités de cette roche sont recouvertes d’une couche 
caleaire agglomérée avec des restes d’animaux, des coquilles, de coraux, et de 
madrépores.” } 
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 Physique, ete. de l'fle de Cuba, Tom. I. p. 110. 
