I06 ABSTRACTS 



Nevada are, with minor exceptions, pretty closely confined to the belt 

 of Palaeozoic and Juratrias slates with their associated greenstones and 

 included granitic masses. The area covered by these rocks forms the 

 real gold belt of the Sierra Nevada. It is gratifying to announce that 

 the geological work covering this area is now nearly completed. The 

 Marysville, Smartsville, Sacramento, Placerville, and Jackson folios 

 are published, and the Bidwell Bar, Downieville, Truckee, Pyramid 

 Peak, Big Trees, and Sonora sheets are soon to be published. Atten- 

 tion was called to the very extensive beds of Juratrias tuffs in the foot- 

 hills, indicating enormous volcanic activity in Juratrias time. Later 

 in the Tertiary the scene of volcanic activity was transferred to the 

 crest of the range, and nearly the whole area of the gold belt was 

 flooded with lavas chiefly of a rhyolitic and andesitic character. 



Shore Lines of Lake Warren and of a Lower Water Level in Western- 

 Central New York. By H. L. Fairchild. 

 This paper describes the eastward extension of the Warren shore 

 line as discovered and traced by the author during the past summer. 

 The beach, in excellent form, with the various shore-line phenomena, 

 as cliffs, bars, spits, and hooks, has been traced from Crittenden to 

 Lima, somewhat east of the meridian of Rochester ; while sufficient 

 evidence of static water at a corresponding level is found much further 

 eastward. The altitude of the beach between Batavia and LeRoy is 

 880 feet above tide. The altitude at Lima, subject to possible correc- 

 tion of datum, is 877 feet. This water plane would lie just about 500 

 feet over the Iroquois plane and would apparently lie below the plane 

 of Watkins Lake or of Lake Newberry, the early local glacial waters in 

 the Seneca embayment. It therefore seems certain that the Warren 

 waters never found outlet by the Horseheads channel. The comparison 

 of the beach phenomena east of Indian Palls with the same phenomena 

 at Crittenden and westward is difficult to make on account of the dif- 

 ference in the topography of the country. East of Indian Falls the 

 beach is transverse to the drumloid molding of the land surface, and 

 the beach is not of so mature a character as south of Lake Erie, but 

 nevertheless indicates a long period of wave action. Another beach 

 at an altitude of 700 feet has been found at Geneva, New York, and 

 traced westward continuously nearly to the meridian of Canandaigua. 

 Abundant evidence of the same water plane is found in terraces and 

 cliffs nearly to the Genesee River. The phenomena of this shore line 



