368 O. E. JENNINGS 
mouth the whole surrounding region can be seen to have been 
rescued from the sea by the united efforts of the river and the 
mangrove. 
The twenty-mile trip from Nueva Gerona to Los Indios, on the 
western coast of the island, was made by automobile, going south 
from McKinley across the level and fairly fertile plain constituting 
the upper drainage basin of the Rio de las Nuevas. The ridge form- 
ing the divide between this river and the rivers draining toward 
Los Indios was found to have rather easy slopes, with but little rock 
exposed, this rock being a quartz-mica schist. Toward Los Indios 
we soon dropped to a slightly elevated level plain whose surface in 
places consisted of considerable areas of glistening white angular 
quartz pebbles and was almost bare of vegetation. As noted by 
Hayes, there is considerable iron lying about in places, evidently 
left after the erosion of the soft schist. Much of this surface iron 
was noted in a trip made from Los Indios to the highest point of 
La Canada range about 6 miles west of the town. 
The Sierra de la Cafiada was supposed by Hayes’, judging from 
its topography viewed from a distance, to be of the Gerona Marble; 
but the ridge is made up of quartz-mica schists, distinctly banded, 
with a general northeast dip. The southwestern exposure is quite 
steep and precipitous and probably owes this character to wave- 
cutting during a past period when the land stood at a different level, 
as is so clearly shown around the bases of the marble mountains in 
the northeastern part of the island. The top of the ridge was 
found to attain a height of 985 feet, by barometer, and access was 
fairly easy by following up the ravines and along the rather gentle 
slopes of minor ridges. The whole ridge is covered by a sparse 
pine and star-palm vegetation wherever the plants can get a foot- 
hold. At the base of the steeper side of the ridge is a well-developed 
talus slope, and from this stretches away immediately the quite 
level sandy or gravelly plain, pine-covered clear to the coastal 
fringe. Willis, in his ‘Index’? has unfortunately accepted the 
erroneous supposition as to the character of the Sierra de la Canada. 
= (OD Gia Do Witt 
2 Bailey Willis, “Index to the Stratigraphy of North America,” Professional 
Paper 71, U.S. Geol. Surv., 1912, p. 340. 
