of the Specular Iron-Ores of Santiago de Cuba. 417 
flank of the Sierra Maestra and middle foot-hills are covered 
with a mantle of the same trappean rock. e maximum 
thickness of this mantle I estimate to be about 2000 feet, cor- 
responding to an altitude of about 3800 feet. 
The Sierra Maestra is the south (front or coastward) range, 
and last elevated, as well as the longest, of a series of succes- 
Reference will presently be made to the more special litho- 
logical features of both ranges, within the limited scope of my 
observation. Occasion is here suggested to note as a signifi- 
cant fact in relation to the vuleanism of the Sierra Maestra, the 
family relation of the two types of eruptive rocks entering 
into the structure of at least the base and south flank of this 
range. The significance of this fact, in connection with others 
that will be noticed, appears to be that the overweighting of 
the syenyte mass along an inherent line of Jeast resistance, 
corresponding to the margin of the sub-oceanic basin of the 
Caribbean Sea, has been followed first by depression, attended 
with re-melting of the base of the mass: and afterward by 
elevation. This elevation, it will be shown, has taken place 
y successive stages. The final, if not the concurrent, result 
of such oscillations of level has been to inject the molten 
magma in the form of dioryte through fissures incidental to 
elevation 
The diorytic mantle thins off toward the coast, in part by 
erosion, while the lower ranges of foot-hills are completely 
denuded of dioryte, if ever enveloped. 
The immediate coast presents a remarkable development of 
coral rock, or coral limestone, in three terraces, of which the 
upper is about 350 feet above the sea. The second terrace is at 
an altitude of about 175 feet, and the present shore, a plateau 
of comparatively recent elevation, about 14 feet above tide. 
These terraces mark successive elevations of the Sierra Maestra 
range. These stages of elevation were in direct, but probably 
remote, succession with other elevations which I shall show to 
be indicated by traces of more ancient corallines (coral forma- 
4 
