308 
APPENDIX II. 
level. The existence of these masses of coralline lime- 
stone indicates clearly a lower level of the island, and the 
evidence of raised beaches confirms this. But a considera- 
tion of the coral reefs points as clearly to a time when 
the island stood at a higher level. The present coral reef 
fringes the coast, extending, as I have mentioned, about 
three miles on the south-west side, but coming close in 
shore on the east. An older reef, however, exists, now 
quite submerged in some places to a depth of over 90 
fathoms. Upon it the present reef rests, and it extends 
westwards nearly fifteen miles from the present coast, 
while on the east it stretches about six miles. We have 
thus proof of great and intermittent oscillations of the 
level of the island. Of the islets scattered over the reef 
some are volcanic and the others are composed of coralline 
limestone and sand. They are all within the compass of 
the present reef, and only occur on its wider parts.’ Eight 
islets are of volcanic origin ; the coralline limestone and 
small islets are more numerous, and are confined to the 
southern and western reefs ; none occur on the north. 
Mr. W. 0. Crosby 1 states that level terraces with 
vertical walls, resting against the rugged mountains of the 
interior, and forming the shore of the island, are conspi- 
cuous features in the scenery of Cuba. They may be ob- 
served at various levels up to nearly 2,000 feet. The first 
preserves a sensibly uniform altitude of about 30 feet for 
hundreds of miles. It is breached by the rivers which flow 
into the sea, and is seen to be composed of coral : in sheet, 
it is an elevated fringing reef, similar to that which is now 
forming on the adjacent sea bottom. It varies in width 
from a few rods to a mile or more. Sand and gravel are 
occasionally interstratified, especially near the rivers, 
showing that they are older than the reef. 
1 On the elevated Coral Reefs of Cuba, by W 0. Crosby. Proo, 
Boston Nat. Hist. Soc. vol. xxii. (1882-3), p. 124. 
