W. M. Gabb—Notes on Costa Rica Geology. 199 
say that such mines do not, and for sufficient geological reasons 
cannot, exist there. This, however, is not surprising to one 
who has been in California or in the West Indies, where such 
traditions exist everywhere. Having now completed the field- 
work of this little isolated region, I consider it advisable to put 
on permanent record a bare resumé of the leading facts and ob- 
servations, leaving all theories and deductions for a future oc- 
casion. It is difficult, and perhaps unadvisable, to attempt to 
generalize where one’s observations have been so entirely cir- 
cumscribed as mine have been in this district. I have not 
been able to carry my observations to the Pacific; and the con- 
glomerate rocks, of which I shall speak, point to older sedi- 
mentary formations which I have not seen, and which ma 
have played an important part in the history of Isthmian 
America. 
The central Cordillera of the lower part of Costa Rica is 
not much less than 6,000 feet high at its lowest point. Along 
this crest rise several prominent peaks, that of U-jum, at the 
head of the Coen River, and Mt. Lyon, at the head of the Lari, 
being probably over 8,000 feet each, while Pico Blanco, or 
Kamuk, the culminating point, is 9,652 feet, by careful baromet- 
_ rical measurement. Farther down the isthmus the reputed vol- 
canoes of Chiriqui and Robalo are said to be of corresponding 
eights; but to the northwest a decided depression of the 
range occurs, before we reach the high region of Central Costa 
Rica. The direct distance from the summits of the range to the 
forests and impassable swamps, and so rly supplied even 
with Indian trails, that the distance travelled is fully three 
times as n open country, with good routes of travel, 
of the hardest la 
the coast is bordered by a flat region of swamp, broken by only 
a few low spurs. . . 
