78 



THE ILLINOIS GLACIAL LOBE. 



had just been excavated in till. Upon classifying- the rocks the following 

 results were obtained: 



Pebbles classified from an eslcer and the till near Forreston, Illinois. 



Granite 



Dark-colored basic eruptives 



Red quartz-porphyry '. 



Quartzite 



Quartz 



Siliceous shale and thin-bedded sandstone 



Brown chert 



White chert 



Yellow limestone, largely Galena 



Blue and gray limestone (Lockport and Trenton) 



Total 



Several fossils were found in pebbles of Lockport limestone, and also 

 characteristic fossils of the Trenton and Galena, both by the writer and by 

 other persons who have discussed this ridge. As the latter formations have 

 an outcrop for only 40 or 50 miles to the east, the material may confidently 

 be considered of local or semilocal derivation. 



Hazeihurst esker. — A short esker is found near Hazelhurst, at the borders of 

 Ogle and Carroll counties. (See PI. XII.) The esker proper is a sharp 

 ridge about 1J miles in length, rising just west of Hazelhurst to a height of 

 fully 100 feet above the station and maintaining a height of 60 to 75 feet 

 for a distance of nearly a mile. Its eastern end is about a half a mile east 

 of the village, and the western end about a mile northwest. The ridge is 

 practically continuous, but has a slight deflection in its middle portion, one 

 ridge terminating and another beginning a short distance south and immedi- 

 ately opposite the end of the former. The general trend of the esker is 

 east to west, but the western end points northwest. There is no delta-shaped 

 deposit of gravel at the western end. On the contrary, the ridge contains 

 considerable till at that terminus. Several gravel pits have been made in 

 the ridge near its eastern end, which show it to be composed, like that of 

 the esker in Leaf River Valley, of very coarse material at the top and finer 

 material in the basal portion. The pebbles are mainly limestone of local 

 or semilocal derivation, as in the esker just discussed. 



