718 THE ILLINOIS GLACIAL LOBE. 



feet in depth, and wells are often sunk some distance into the underlying 

 limestone. 



At Beverly the village well is 73 feet in depth, and apparently enters 

 a preglacial sand in the lower 20 feet. This interpretation is made, how- 

 ever, from the examination of a well in process of excavation about one- 

 half mile east of the village, at the residence of J. Sykes, the section of 

 which appears on page 60. Mr. Sykes's well penetrated an orange-colored 

 quartz sand in its lower 15 feet, which is entirely free from calcareous 

 material and is apparently much older than the glacial drift. It so happens 

 that at this well there occurs at the base of the glacial drift a bed of gravel 

 and sand which is highly calcareous, and is much fresher in appearance 

 than the quartz sand just referred to, a feature which lends much support 

 to the interpretation of the preglacial age of the orange-colored sand. 



Along the Illinois-Mississippi divide northwest from Beverly wells 

 occasionally reach a depth of 90 feet without entering solid rock. They 

 are reported to pass through an orange-colored sand in the lower part, which 

 is probably similar to that examined in the well at Mr. Sykes's. Probably 

 further study in the region would result in the discovery of natural expo- 

 sures, for the ravines leading eastward from this divide are frequently cut 

 to sufficient depth to reach the level of the orange-colored sand. 



PIKE COUNTY. 

 GENERAL STATEMENT. 



Pike County is situated between the Mississippi and Illinois rivers, 

 immediately south of Adams and Brown counties, and has an area of 795 

 square miles, with Pittsfield as its county seat. Fully three-fomihs of the 

 county is tributary to the Mississippi River. It is probable that a larger 

 portion is now tributary to the Mississippi than in preglacial times. As 

 noted on page 480, the headwater portion of Bay Creek leads southeast- 

 ward, as if to join the Illinois, but a morainic ridge on its east border 

 prevents its entering the Illinois, and it passes westward through a hilly 

 region which probably once constituted the divide between the Mississippi 

 and the Illinois, and thus becomes tributary to the Mississippi. 



The interior portion of the county is traversed by a sei'ies of drift 

 ridges, which are the continuation of those noted in Adams County, and 

 which, like those of Adams County, have a northwest-southeast trend. 



