MODIFIED DRIFT OF THE LAKE DISTRICT. 



135 



deposits have been used for brick-making, and the latter has been exca- 

 vated at two places an eighth of a mile apart. It is overlaid by about two 

 feet of till, and a well showed the thickness of clay to be 13 feet, under 

 which was a water-bearing layer of gravel. 



From this clay-bed a valley about 40 feet in depth descends to the 

 south at the west base of the hill, which on this side is ledge. The bot- 

 tom and the steep west side of 



,V-''^ Clay beds. 



Lines of sectio 

 as shown 

 Fig. 34. 



t a ^ ! ' 

 Fig- 33- — Map of a small area in Altox, 



TWO MILES SOUTH FROM ClAY PoINT. 



Scale, I inchrri mile. Contour lines are 

 shown for each 10 feet, the highest being 

 200 feet above the lake. 



the valley are composed only of 

 modified drift, being fine silt or 

 sand ; while only till with many 

 large angular boulders up to 10 



Upper till. Sand. Ledge. 



Fig. 34. — Section crossing Fig. 32. 



Horizontal scale, i inchml mile ; ver- 

 tical scale, I inchz:r4oo feet. The 

 dotted line at the base represents 

 the level of the lake. 



feet in size forms the top of its west bank and the irregular surface, 

 which thence descends westerly to the alluvial area previously described 

 on jDage 129. The contour of this locality is shown in Fig. 33 ; and Fig. 



34 shows the apparent position of the sand 

 underlying the very coarse till. Less than 

 a mile farther south a similar valley is seen 

 from the highway on its east side a short 

 distance north of M. Adams's house. The 

 contour and probable section at this place 

 are shown in Figs. 35 and 36. Here it 



Upper till. Sand. Upper till. 



Fig- 35- — Map of a small area 

 IN Alton, three miles south 

 from Clay Point. 



Scale, I inch=::J mile. Contour 

 lines are shown for each 10 feet, 

 the lowest being 50 and the 

 highest 200 feet above the lake. 



Fig. 36. — Section crossing Fig. 35. 

 Horizontal scale, i inchz:::^ mile; vertical scale, 

 I inch=40o feet. The dotted line at the base 

 represents the level of the lake. 



