. The Andes of southern Peru; geographical reconnaissance along the seventy-third meridian. Yale Peruvian Expedition (1911); Physical geography; Geology. 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
. The Andes of southern Peru; geographical reconnaissance along the seventy-third meridian. Yale Peruvian Expedition (1911); Physical geography; Geology. 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 Please note that
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Keywords: ., bookauthorbo, bookcentury1900, bookdecade1910, booksubjectgeology
