GLACIAL STRIJE. 87 



about as high as are reached by the limestone in that vicinity. These 

 surfaces had been exposed by the removal of till in the railway cuttings 

 and were overlain by several feet of unmodified till. The glacial origin of 

 these stria? seems supported, therefore, by the character of the striation, the 

 position of the strife, and the character of the overlying beds. 



The stria? observed by Prof. G. F. Wright in Jackson and Williamson 

 counties, Illinois, are the southernmost ones yet found in the drift-covered 

 region of eastern North America. Wright states that the glaciation is as 

 heavy as is often found at points some distance within the glacial boundary. 

 They are scarcely more than 5 miles from the extreme limit of glaciation, 

 and bear directly toward the glacial boundary. Those noted by the writer 

 a few miles northwest from Murphysboro are also very heavy glacial 

 grooves and are situated equally near the glacial boundary. 



The stria? in Greene and Owen counties, Indiana, are usually found on 

 a firm sandstone. Those observed by the writer near Worthington are 

 heavy grooves. The character of the glaciation at points reported by other 

 observers appears from descriptions to be as vigorous as at the points just 

 considered. The remarkable variation in bearing in Owen County is 

 worthy of further investigation. 



The bearings of the striae in the vicinity of the Wabash Valley in 

 Clark County, Illinois, and in Vigo and Sullivan counties, Indiana, give 

 rise to some surprise, for the stria? appear to show no disposition to radiate 

 toward the neighboring portion of the glacial boundary on the southeast. 

 Dr. J. T. Scovell, who made all these observations in the vicinity of the 

 Wabash, reports that there is heavy glaciation at each exposure. 



In the list of stria? given below four exposures are reported from 

 northern Illinois which are situated within the limits of the Iowan drift. It 

 is not certain whether they were produced at the Iowan invasion or at the 

 Illinoian. They appear to be in harmony with the general movement of 

 the ice sheet at the Illinoian stage as well as at the Iowan. These exposures 

 were in each case first observed and reported by Mr. I. M. Buell, and are 

 said to be very faint compared with the stria? seen by him within the limits 

 •of the Wisconsin invasion. The list given below is restricted to the district 

 outside the Wisconsin drift, the stria? within the limits of the latter drift 

 being included in a table presented later (pp. 412-414). 



