SUNKEN PACIFIC LAND 
331 
since very remote geological times, while its ancient moun¬ 
tain system, trending in a west-eastward direction, abruptly 
terminates on the Pacific coast. I ventured to explain 
the many instances of curiously discontinuous distribution 
in Central America by the supposition that an ancient land 
occupied the adjoining portion of the Pacific, and that the 
present Central America is partly formed of the remnants of 
that land having eventually become moulded together by geo¬ 
logically recent volcanic deposits. If we assume that the Cape 
Region of Lower California belonged to that Pacific land 
which really formed the southern continuation of the north 
Pacific belt of land alluded to, a reasonable explanation is 
advanced for the faunistic affinity of the Cape Kegion to 
Central America, the West Indies and Asia, and its dissimi¬ 
larity with the rest of Lower California. The hypothesis of a 
former westward continuation of portions of Central America 
is not founded purely on zoogeographical considerations. 
In his reference to the older Tertiary sediments of Central 
America Professor Hill* states that it is impossible to avoid 
the conclusion that they were derived from a near-by 
land which existed at the time of their deposition. The only 
hypothesis, he says, that can fit the condition of their 
present lay and arrangement is that this land existed 
towards the Pacific coast or in the area now covered by the 
Pacific waters of the Isthmian Region. The “ old land ” 
or early representative of the isthmus of Panama, remarks 
Mr. Hershey,f la.y mainly south of the present isthmus. 
That it was a land-mass of considerable extent, be con¬ 
tinues, is indicated by the heavy beds of conglomerate 
formed from it, and he argues that the peninsula of Azuero 
which projects out into the Pacific is a remnant of this land, 
while on its northern border were laid down the more recent 
formations which make up the main body of the isthmus. 
Geologically there is, therefore, some evidence, too, for the 
assumption of a former extensive land surface on the Pacific 
side of Central America. It must be remembered that while 
Central America as a whole has a south-east and north-west 
* Hill, E. T., “ Geological History of Panama,” p. 263. 
t Hershey, O. H., “ Geology of Isthmus of Panama,” p. 249, 
