336 GEOLOGY OF ILLINOIS. 



blue clays, sand and gravel. At Minonk, township 28, range 2 east, a shaft 

 has been sunk, from which the following section of the Drift was obtained : 



FEET. 



1. Soil 2 



2. Yellow clay -. 14 



3. Blue clay 18 



4. Sand and gsavel 15 



5. Cemented sand and gravel 76 



125 



In section 21, township 28, range 2 west, the Drift exposed in the ravine of 

 Richland creek, presented a different order of arrangement. A section here 

 showed : 



FEET. IN. 



1. Soil and yellow clay. Not measured 



2. Purplish clay or hard pan. Not measured 



3. Blue sandy clay, containing fresh water shells 6 



4. Rotten drift-wood or peaty matter 3 6 



5. Blue clay 3 to 4 



6. Drift-wood or peaty matter 5 "6 



7. Blue clay. Not measured 



In this vicinity, on the uplands, wells are reported to have been sunk to a 

 depth of from fifty to sixty feet, and the hard pan or purple clay not reached. 

 Judging from the hight of the bluff, I should think that Nos. 1 and 2, of the 

 last section, would probably exceed these figures. 



No. 3 contained fragments of fresh water shells, among which the genera 

 Succinea and Limnea were recognized by Mr. Meek. This bed resembles the 

 Loess, but its position, below a considerable portion of the Drift, shows that it 

 belongs to an older formation. 



No. 4 resembles peat, and contains fragments of wood, some of which are well 

 enough preserved to be recognized, but the larger portion has been converted 

 into peaty matter. Among the specimens collected from this bed, the follow- 

 ing kinds of timber were recognized by Prof. Lesquereux: American white 

 birch, black or double spruce, American larch or Tamarach, and one variety of 

 cedar. 



No. 5 resembles No. 3, but no shells were noticed in it. 



No. 6 is similar in character to No. 4. This bed was not as well exposed as 

 the upper one, but was examined by boring through it. Of course, but small 

 specimens could be secured by this method, and the only kind of wood thus 

 obtained, that could be recognized, was the American or black larch. 



These beds appear to have been formed mainly of drift wood, the larger part 

 of which has undergone a partial decomposition. There is too large a percent- 

 age of earthy material intermingled with the peaty matter to be valuable for 



