BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 6, pp. 103-140, PL. 1 January 7, i895 



RECONSTRUCTION OF THE ANTILLEAN CONTINENT 



BY J. W. SPENCER, A. M., ril. D., F. G. S. (l. AND A.) 



{Read before the Society August 14, 1S94) 

 CONTENTS 



Page 



Introduction 103 



Geomorpliy as exemplified in valleys 105 



Deformation of land surfaces 107 



Submarine valleys and fjords of the continental and iVntillean regions 108 



The continental shelf 108 



Drowned valleys or fjords 110 



Characteristics of the lower reaches of the land valleys 117 



Analogy between the submerged valleys or fjords and the land valleys and 



can3-ons, with inferences as to former continental development 118 



Mid-Tertiary subsidence of the region of the AVest Indies 120 



The Antillean continental extension in the Pliocene period 122 



Drowning of the Pliocene lands and burial beneath marine accuniLdations . . . 124 



The earlier Pleistocene Antillean continent and its degradation 128 



Subsidence of tiie West Indies in the later Pleistocene period 129 



Reclevation of the lands at the close of the Pleistocene period 130 



The separation of the Antillean basins from the Pacific ocean and their con- 

 nection with the Atlantic 1 31 



Biologic bearing of the physical changes of level 134 



Summary ] 39 



Introduction, 



For decades a vague impression has existed that some kind of conti- 

 nental extension formerly united the West Indies to the mainland of one 

 or the otlier of the continents, or to both, and that tlie exclusion of the At- 

 lantic currents and the admission of the Pacific waters into the Mexican 

 gulf and Cari])l)ean sea have at some time prevailed. Suggestions have 

 been made as to the necessity of a foreign source for the mechanical sedi- 

 ments found in the islands "which do not })ossess the geological quarries for 

 the supply of such materials. Wallace* has illustrated how the Antil- 



*" Island Life," by Alfred Russell Wallftce, second edition, 1892, p. 26.'i. 

 XV— BiM,. fir.oi,. S(.c. Am.. Vol. fi, 1894. (103) 



