LOESS IN THE WISCONSIN DRIFT FORMATION 935 



like. At this point (Logansville) it is distinctly stratified, in 

 places at least, and constitutes, or at any rate covers, the valley 

 flat. 



Loess-like loam about Baraboo. — In addition to the distinct 

 development of loess at Devil's Lake, the surface of the drift 

 about Baraboo is often marked by loam no less distinct than 

 that about Green Lake. The surface loam does not seem to be 

 restricted to the surface of the drift, but affects the extra- 

 glacial surface as well. Even the high quartzite ridges seem to 

 have a capping of it, though it cannot be affirmed that the loam 

 (or clay) on these ridges is the equivalent of that over the 

 drift. 



The "east bluff" (the quartzite bluff east of the lake), 1560 

 feet above the sea level, and 800 feet above the valley of the 

 Wisconsin five miles to the south, has a goodly development of 

 clay-loam (five or six feet) upon it. This is exposed in but 

 few places, but the sturdy character of the forest shows that 

 there must be some soil other than that which could have arisen 

 from the decomposition of the quartzite. At the spot where 

 the problematical gravel heretofore described occurs^ the gravel 

 overlving the quartzite is covered by five to six feet of nearly 

 stoneless clay loam. Its aspect is such as to suggest its genetic 

 connection with the loess. This loam, or something very like it, 

 whatever its origin, is widespread. Whatever is true of the 

 extra-glacial surface loams, that which overlies the drift about 

 Baraboo seems to belong with that which overlies the drift at 

 Green Lake, and which so frequently grades toward normal 

 loess and sometimes assumes the character typical of that for- 

 mation. I now believe it to be the equivalent of the stoneless, 

 or well nigh stoneless, mantle of clay which occurs at some 

 points about Madison, and which I was formerly inclined to 

 regard as wind-blown dust accumulated on the ice and depos- 

 ited in the final melting.^ In the adequacy of this suggestion I 



'Jour, of Geol., Vol. Ill, p. 655. 



^ Proc. Am. Ass. for Adv. of Sci. 1893, p. 180. See also Ann. Report of the 

 State Geologist of N. J., 1893, pp. 211-24. 



