748 WILLIAM F. JONES 
very plentiful and the beds contain numerous fragments of petri- 
fied wood, often whole trunks of trees. Many of the sands are well 
cross-bedded. There is physiographic evidence to show that the 
region, after uplift and folding, drained to the southeast through 
Santo Domingo across what are now the plains of San Juan and 
Azua. Before the deposition of these non-marine beds the region 
suffered considerable erosion, perhaps through Pliocene time, for 
these beds, which the writer has called the Hinche beds, fill many 
old erosion gullies in the underlying folded earlier series. Drainage 
aos ERS 
Fic. 9.—South side of central plain east of Las Cahobes. Sharp hills formed by 
Las Cahobes beds. 
was then cut off and the region became a lake in which the Hinche 
beds were deposited. The floor of this lake is formed by the 
uppermost Hinche beds and that old floor, intact in the northern 
part of the plain, and largely eroded away in the southern part 
(Fig. 8), forms the surface of the central plain above which stand 
the Las Cahobes beds (see Fig. 9). 
Terrace deposits.—The southern part of the central plain region 
is terraced (see Fig. ro) and on these terraces are loose gravels. 
At least four terrace levels are noted. After the deposition of the 
Hinche lake beds an opening was cut through the limestone range 
south of Las Cahobes and the plain region drained that way, the 
rivers following the Artibonite in its lower valley. This old cut 
