feULLETiN OF THE GEOLOGICAL SOClEtV OF AMEmCA 



Vol. 10, pp. 285-348, PLS. 30-32 MaY 5, 1899 



PHYSIOGRAPHY AND GEOLOGY OF REGION ADJACENT TO 

 THE NICARAGUA CANAL ROUTE* 



BY C. WILLARD HAYES 



{Read before the Society December 29, 1898) 



CONTENTS 



Page 



Introduction ^ 286 



Topography 287 



General character of the topography 287 



Classification of topographic features ; 288 



Types in general 288 



Alluvial plains 289 



Dissected peneplain 293 



Residual hills 298 



Western divide 299 



Lake-Caribbean divide 300 



Volcanic mountain ranges 301 



Volcanic plateaus 304 



Climate 304 



General character 304 



Amount and distribution of rainfall 305 



Physiographic eflSects 305 



Eastern division 305 



Western division 307 



Rock formations ..^^ ^ 308 



Conditions for study '. 308 



Classification of the rocks 309 



Brito formation 309 



Distribution 309 



Lithologic character 309 



Structure , 311 



Age of the formation 312 



Machuca formation 313 



Distribution 313 



Lithologic character 313 



Structure 313 



Age of the formation 314 



♦Published by permission of Rear Admiral J. G. Walker, President of the Nicaragua Canal 

 Commission. 



XLII— Bull. Geol. Soc. Am., Vol. 10, 1898 (285) 



