296 I). F. Lincoln — Glaciation in the 



ingredient of the till. Gneisses and schists are absent, or 

 badly rotted. The forms are characteristic of till, and in some 

 cases striation is observed. A part of the stones react feebly 

 to HC1 ; the clay does not react. 



Midway of the Cayuga lake shore, on the east side, there are 

 fine till sections which give a similar result on analysis. 



The same leaching of the upper part has been observed in 

 stoneless sedimentary clay of Geneva. Absence of the lime- 

 reaction is stated to be characteristic of the soil at the State 

 Agricultural Station in the same town. 



At many points on the surface of the lower-till (Drumlin) 

 deposits just described, there is little or none of the englacial 

 material defined by Upham.* But where the stones lie thickly 

 in the fields it is necessary to suppose that they are chiefly of 

 englacial origin; for the proportion of limestone fragments in 

 such cases is quite too small to permit us to refer them to the 

 lower-till. This is easily seen in the piles of stones which the 

 farmers draw from the fields — sometimes 12-20 feet in diam- 

 eter from a 100-acre lot — consisting mostly of gneissoids, 

 schists, and quartzites, with perhaps one-fifth corniferous lime- 

 stone, the lumps varying from 2 to 200 pounds in weight. 

 The larger stones (bowlders) carry out this statement ; they are 

 almost all far traveled stones. Large bowlders are not very 

 frequent. The largest within observation are one of labrado- 

 rite (7x7 feet), and one of an argillaceous rock from the 

 Salina beds (6x11) which is exceptional in having traveled 

 only 5 or 6 miles. 



Stratified deposits are not infrequent, however, upon the 

 drumlin formation. Rolled gravel is not rare, and the kames 

 and osars deserve a fuller description than can here be given. 



On reaching the higher levels, west of Geneva or east of 

 Aurora, we often find the surface sandy. The sand even takes 

 the form of low hills and ridges. The deposit of tough lower- 

 till, however, is still found beneath the light top-soil. 



The thickness of the till-sheet at Geneva is reported at seve- 

 ral points as 20-30 feet. Sand lies beneath this, and still 

 lower, till again. At one well, there was 14 feet of sand, and 

 13 feet or more of the deeper till bed. Layers of vegetable 

 matter, and blue clay, are also found. 



In passing south from the soft shales of the Hamilton group 

 to the sandy shales and hard fissile sandstones of the upper 

 Devonian beds, we are informed of the change of bed-rock by 

 the alteration in the character of the lower-till. The latter, in 

 recent exposures, may be very tough, but is sandy rather than 

 clayey. The enclosed stones are sandstone, rarely limestone. 

 Fragments handsomely glaciated occur as large as three feet 



* Amer. Geologist, vol. viii, No. 6. 



