Reviews 



SUMMARY OF THE LITERATURE OF NORTH AMERICAN 

 PLEISTOCENE GEOLOGY 1901 AND 1902. III. 



Frank Leveret t. 



UNITED STATES. 



PENNSYLVANIA. 



Campbell, M. R. The Masontown- Uniontown Folio. Geol. Atlas of the 



United States, U. S. Geol. Survey, Folio 82, 1902. 



The matters pertinent to this review are the drainage features and the Pleisto- 

 cene deposits. The valleys of the main streams in this folio, as in much of western 

 Pennsylvania, carry gradation plains into which deep and comparatively narrow 

 trenches have been cut since the beginning of glaciation. The trenches have not yet 

 extended to the headwaters of the tributaries. The Monongahela has made singular 

 departures from its old course, which the author thinks are attributable to blockades 

 of the old courses by river ice concurrent with the glaciation in districts to the north, 

 a view which he had previously expressed in the Huntington, W. Va., Folio. (See 

 Review.) Prior to the cutting of the trench, and coincident perhaps with the diversion 

 of the river into its new course, the valley became filled greatly with alluvial material, 

 but much of this filling has been removed by interglacial and postglacial stream 

 erosion. The rock floor stands about 900 feet above tide, or not far from 150 feet 

 above the river, but the filling reaches 250 feet or more above the stream. 

 Griffith, William. An Investigation of the Buried Valley of Wyoming 



[Pennsylvania]. Proc. Wyoming Hist, and Geol. Soc, Vol. VI, pp. 



27-36, with map, 1901. 



The valley is filled with gravel and sand and coarser drift to the depth of 200 or 

 300 feet. Were this filling removed, there would be a lake eighteen miles long and a 

 mile in width, through which the Susquehanna River would flow. This river now 

 flows along the surface of the gravel bed, but slightly impinging upon the rock rim. 

 It is evident that this gravel is permeated by water, for sometimes in mining opera- 

 tions both gravel and water rush into the mines that pass into the limits of the gorge, 

 and this has been the cause of much difficulty and some fatalities in the mining of 

 the coal at Wilkesbarre. (From review by N. H. Winchell in American Geologist, 

 Vol. XXVIII, p. 324.) 

 Williams, E. H. The Alleged Parker Chan7iel. Bull. Geol. Soc. Am., 



Vol. XII, p. 463, igoi. 



The view is presented that the oxbow, which had hitherto been referred to 

 the preglacial Clarion River, is instead made up of two short side valleys that 

 headed on opposite sides of a low col and debouched into the Allegheny within a 

 mile of each other. In glacial time these two valleys were greatly filled by gravel 

 brought down the Allegheny, and also by wash from adjacent hills. 



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