Bulletin of the Museum of Comparative Zoology 
AT HARVARD COLLEGE. 
Vor. XXVIII. No. 6. 
(GEOLOGICAL SERIES, Vor. III.) 
THE GEOLOGICAL HISTORY OF THE ISTHMUS OF 
PANAMA AND PORTIONS OF COSTA RICA. 
BASED UPON A RECONNOISSANCE MADE FOR ALEXANDER AGASSIZ. 
By Коверт T. HILL, 
WITH SPECIAL DETERMINATIONS BY 
WILLIAM Н. Darr, В M. Baco, Т. W. VAUGHAN, J. E. WoLrr, Н. W. Turner, 
AND AHE SJÓGREN. 
Wun NINETEEN PLATES. 
CAMBRIDGE, MASS., U.S.A.: 
PRINTED FOR THE MUSEUM. 
Док, 1898. 
