PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 245 



traverse opportunity was not afforded for further study of this 

 aspect of the series, since our route led generally along the strike 

 rather than along the dip of the beds. It is interesting to note, 

 however, that these observations as to the increasing amounts of 

 clastic material in a westward direction were afterwards con- 

 firmed by Senor Jose Bravo, the Director of the Bureau of Mines 

 at Lima, who had found Carboniferous land plants in shales at 

 Pacasmayo, the only fossils of A 



their kind found in Peru. For- 

 merly it had been supposed that 

 non-marine Carboniferous was 

 not represented in Peru. From 

 the varied nature of the flora, 

 the great thickness of the shales 

 in which the specimens were col- 

 lected, and the fact that the 

 dominantly marine Carbonifer- 

 ous elsewhere in Peru is of 

 great extent, it is concluded that 

 the land upon which the plants 

 grew had a considerable area 

 and probably extended far west 

 of the present coast line. Since 

 its emergence it has passed 

 through several orogenic move- 

 ments. These have resulted in 

 the uplift of the marine portion 

 of the Carboniferous, while the 

 terrestrial deposits seem to have 

 all but disappeared in the down-sunken blocks of the ocean floor, 

 west of the great fault developed along the margin of the Cordil- 

 lera. The following figures are graphic representations of this 

 hypothesis. 



The wide distribution of the Carboniferous sediments and 

 especially the limestones, together with the uniformity of the fos- 

 sil faunas, makes it certain that the sea extended entirely across 



/XL! MESTONE^Z 



WBMft 

















S ■•'*'•' ; ( ■ 













_ SHALE AND J- 



= SANDSTONES^ ' 



. QUARTZITES ' . 1- -^M[fl 











A B 



Fig. 164 — Geologic sketch map and 

 section, Antabamba region. The Anta- 

 bamba River has cut through almost the 

 entire series of bedded strata. 



