264 BULLETIN OF THE 
ancient and older plateaus, which, when their limestone cap is finally 
removed down to the metamorphic base, will assume the Villa Clara 
type. 
The drainage system of Cuba is extensive. In general the streams 
flow from the central axis toward the opposite coasts, and are of the type 
which modern geographers would term simple consequent or autogenous 
streams. They have light-colored blue water like that of the. limestone 
springs of Florida and Texas, and in many cases obtain their supply 
from the underground waters of the limestone region. Where seen 
throughout the interior upland plateaus of Cuba they are small in 
volume, and flow in slightly indented channels in wide valleys, and are 
remarkably free from the incisions of lateral drainage. A typical stream- 
way is shown on Plate IX. They do not possess deep barrancas or 
caiions until they begin to cut across the edge of the Cuchilla plateaus 
near the coast. In many cases these rivers are intermittent, disappear- 
ing into and reappearing from the cavernous limestones. As they ap- 
proach the escarpments of the coastal platforms, they reach the sea either 
by sinking into the limestone, by tumbling cascades, or by cutting deep 
vertical cations. They are all slightly tidal at their mouths, the salt 
water extending at high tide a short distance up them, but never reach- 
ing far inland of the soboruco. Most of them bring down to the coast 
the metamorphic and igneous rock of the old nucleal foundation, but in 
no case have I observed limestone fragments, although the rivers must 
degrade and transport in solution far more lime than any other material. 
The vertical cations in some cases, like that of the Yumuri of the east, 
extend to the sea, and testify to the rapid rising of the land, confirming 
the story of the cliffs and base levels as will be described later. (See 
Plate I. Fig. 6.) 
Perhaps the most important factor in the evolution of the topographic 
conditions of Cuba is the superficial and underground destruction and 
alteration of the limestones by solution, heretofore mentioned. Owing 
to the porosity of the limestone rocks, the drainage of Cuba is largely 
underground in the limestone regions, and flowing surface streams and 
lateral drainage channels, such as the dendritic headwater ramifications 
so common elsewhere, are notably scarce in the higher region inland 
from the coast, and the upland limestone region seems to be dissolving, 
rather than corrading, into a sink-hole topography of vast proportions. 
The Coastal Topography. — None of the topographic features of Cuba 
are so peculiar as the innumerable subcircular harbors? which indent its 
1 See Agassiz, Bull. Mus. Comp. Zoél., Vol. XX VI. No. 1, Plates XIII., XIV. 
