Vol. 68.1 THE GEOLOGY OF COSTA BICA. 105^ 



II. Previous Liteeature. 



Reference has been made by many writers to Costa Rican 

 geology ; but, as might be expected, the literature is very scattered 

 and difficult to trace. Many of the papers deal almost exclusively 

 with the chain of recent volcanoes, a subject not dealt with in these 

 pages ; though I cannot claim to have been able to cover, in any 

 sense completely, the previous writings on Costa Eican geology in 

 general, it appears that comparatively few of these make direct 

 reference to the part of the country which is about to be described, 

 and, as this communication is essentially confined to descriptive 

 work, the following list is restricted to those papers which have 

 a direct bearing on the area in question. From this point of view 

 the undermentioned are the most important papers : — 



Attwood, G-. ' The Geology of a Part of Costa Rica,' with appendix by W. H. 



Hudleston. Q. J. G. S. vol. xxxviii (1882) pp. 328-39. 

 GrABB, W, M. ' Notes on Costa Eica Geology ' Am. Journ. Sci. ser. 3, 



vol. ix (1875) pp. 198-204, 320. 

 Sapper, K. ' Ueber Gebirgsbau & Boden des siidlichen Mittelamerika ' 



Peterm. Mitth. Erganzungsb. xxxii (1906) No. 151, pp. i-vi, 1-82. 

 Chdrch, G. E. ' Costa Rioa ' Geogr. Journ. vol. x (1897) pp. 56-84. 

 Hill, R. T, 'The Geological History of the Isthmus of Panama & Portions 



of Costa Eica' Bull. Mus. Comp. Zool. Harvard, vol. xxviii (1898) 



pp. 151-285. 



It is unnecessary to give a synopsis of the work of the authors 

 enumerated above, since throughout the following pages reference 

 is made to their observations as occasion arises ; while occasionally 

 allusion is made to other memoirs dealing less directly with the 

 subject under investigation. If there have been any omissions, which 

 I am afraid may be the case, I can only trust that due allowance 

 will be made for the difficulties encountered in dealing with so 

 wide and varied a. subject. 



III. Geology op the Cerro Caistdelaria. 



The Cerro Candelaria is the range of mountains forming the 

 southern boundarj^ of the wide valle}^ ^ in which San Jose is 

 situated. This range rises with surprising abruptness from the 

 level floor of the valley to a height of some 3000 feet above it, 

 while the general trend of the range in the San Jose area is east and 

 west. These mountains are typical of the hill topography which 

 characterizes the country. The slopes are steep,, often culminating 

 in almost vertical cliffs, while the sides of the mountains are scored 

 by deep narrow ravines separated from each other by sharp saddle- 

 ridges. The whole surface is thickh' clothed in dense scrub, 

 making it almost impossible to leave the recognized trails. The 

 topography is precisely what would be expected during the early 

 stages of denudation, when easily eroded rocks are exposed to 

 rapid and often violent stream-action. 



1 For the sake of convenience, this valley will througliout these pages be 

 termed the 'San Jose Yalley' ; as will be explained later, it is not a river- 

 valley, and to refer to it as the ' Eio Grande Valley' might be misleading. 



