REVIEWS 103 



valleys; and (2) the form of the range does not agree with the struc- 

 ture of its bed rock series, which latter is variously folded and tilted, in 

 ways not expressed by the physiography, and shows varying degrees 

 of obliquity to the front of the range. 



The great erosion of the fault scarp, and lack of erosion of the 

 basalt at its base, shows that the valleys have, during the history of the 

 range as a faulted block, been anything but seats of great erosion ; and 

 the great thickness of alluvium and lake deposits shows that they have 

 been areas of deposition. 



The following papers for lack of time were read by title : 



The Probable Cause of Water Flow hi the Mines of Cripple Creek, 

 Colo. By RuFUS M. Bagg, Jr., Brockton, Mass. 



The Paddles of Shastasauriis . By John C. Merriam, Berkeley, 

 Calif. 



The Qiiater7iary of the Middle Coast Ranges of California. By 

 Andrew C. Lawson, Berkeley, Calif. 



Andrew C. Lawson, 



Secretary. 



AUTHORS' ABSTRACTS OF PAPERS READ AT THE WASHINGTON 



MEETING OF THE GEOLOGICAL SOCIETY 



OF AMERICA. 



Direction of Flow of the A?icie?tt Beaver River, Shown by Pot-holes. 

 By Richard R. Hice. 

 The evidence of the slope of the remaining fragments of aban- 

 doned fluvial plains may not always be conclusive as to the direction 

 of flow of the stream that formerly flowed over them. Pot-holes, one 

 of the features of stream erosion, are conclusive. On the Beaver 

 River from Beaver Falls to below the Fallston dam, the present chan- 

 nel, cut in the Homewood Sandstone, is marked by typical pot-hole 

 erosion. Views of pot-holes below the Fallston dam show in all 

 cases that the up-stream side of the hole is abrupt, and often under- 

 cut, while the down-stream side is rounded off and eroded by the 

 action of the flowing water. This also applies to channels formed by 



^Science, September, 190 1, p. 457- 



