. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 106 bulletin: museum of comparative zoology. the states of Parana and Sao Paulo. Near the town of Sao Pedro de Itarare at the raihvay bridge this river flows in a channel which at one point in its cross-section is not more than three feet wide. The channel lies in the white Devonian sandstones which present no great variation from layer to layer offering opportunity for the. Fig. 29.— Map of the Parahyba and Tiete rivers in Sao Paulo (After H. WilUams). selective solution which in limestone countries often produce sim
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 106 bulletin: museum of comparative zoology. the states of Parana and Sao Paulo. Near the town of Sao Pedro de Itarare at the raihvay bridge this river flows in a channel which at one point in its cross-section is not more than three feet wide. The channel lies in the white Devonian sandstones which present no great variation from layer to layer offering opportunity for the. Fig. 29.— Map of the Parahyba and Tiete rivers in Sao Paulo (After H. WilUams). selective solution which in limestone countries often produce similar gorges. The bottom of this gorge is said to be between 62 and 63 meters below the railroad bridge. At one point west of the railway bridge there is a natural bridge of the sandstone which evidently points to the origin of this gorge as an underground stream. It remains to note the curious course of the Parahyba in relation to the headwaters of the Rio Tiete in eastern Sao Paulo. The annexed map, traced from that of Sao Paulo by Mr. Horatio Williams, late of the Sao Paulo Geographical and Geological Commission, sets forth the pattern of the streams. (Fig. 29,) It will be noted that the upper course of the Rio Parahyba under the name Parahytinga follows a southwest course to the great bend at Guarerema whence the course is northeastward to the sea beyond the limits of the map. These courses are in essential adjustment to the structure of the underlying Pre-Devonian rocks but the basin of the river below the great bend is largely formed by the Tertiary non- marine beds before mentioned. The great bend is made by a trans- verse gorge cut through the Pre-Devonian series which rise a few hundred feet above the riverplain. It is therefore to be presumed that the course of the river at this point is inherited from a former course which lay at the level of the intervening hill-tops. This earlier. Please note that these images are extracted from scanned page images that may have b
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Keywords: ., bookauthorha, bookcentury1900, bookdecade1910, booksubjectzoology
