150 PLEISTOCENE OE INDIANA AND MICHIGAN. 



In the transition belt, on the inner border of the moraine, till of clayey texture is the prevalent 

 deposit both on the ridges and on the intervening till plains. Some of the sharpest ridges and 

 knolls, however, contain assorted material either in pockets or in beds. 



THICKNESS. 



Depth, to rock. — Rock has been struck in deep wells at White Pigeon and Constantine south 

 of this moraine and may have been reached in the waterworks well at Three Rivers. At White 

 Pigeon the distance to rock is at least 182 and possibly 240 feet, there being a record of sand 

 under so-called shale at 212 to 240 feet from the surface that leads to the suspicion that the 

 "shale" is hard till; there is 140 feet of sand and gravel before reaching any till. At Constan- 

 tine the drift is 136 feet thick, and at Three Rivers it may not exceed 100 feet. The wells at 

 all these places are on ground whose altitude is about 800 feet. The altitude of the rock surface 

 is, therefore, only 700 feet at Three Rivers and is considerably less at the other two villages. 

 If this low altitude is maintained beneath the high part of the Sturgis moraine, as seems prob- 

 able, there is possibly about 400 feet of drift in and beneath the highest knolls. The deepest 

 recorded boring on the high tract in Newberg Township, Cass Comity, is in sec. 21, where 199 feet 

 was penetrated and no rock was struck. Several wells in this and neighboring sections are over 

 100 feet deep, and W. F. Cooper estimates the average depth of wells for the township to be 

 97 feet. The amount of drift in this region can be roughly estimated by comparing the map of 

 rock contours (PI. II) with the surface contour lines of the topographic map (PI. I). 



Well data. — At Sturgis the waterworks wells have been sunk 140 feet without reaching 

 rock and are thought by the superintendent to have been largely through sand and gravel. 



Wells on the borders of Klingers Lake have artesian head about 20 feet above lake level 

 and many of them flow. They range in depth from 20 to 80 feet, passing through layers of 

 hardpan or cemented gravel and perhaps some till. 



In the transition belt in western Branch County most of the wells are 20 to 40 feet deep, 

 though a few tubular wells reached depths of 75 to 100 feet, largely through clayey till. The 

 deepest wells are on the ridges. 



In southeastern Kalamazoo County on the undulating till tract near Fulton one boring 

 reached a depth of 275 feet without striking rock or obtaining water. It is reported to have 

 been entirely through a clayey till, which apparently forms a more continuous sheet than it 

 does in the districts south of St. Joseph River. 



OTJTWASH. 



The principal outwash connected with the Sturgis moraine lies on the outer border of the 

 main part of the moraine, but, as already indicated, small outwash plains he between the 

 constituent ridges in St. Joseph and southwestern Branch counties, and outwash plains are 

 also developed in the transition belt along the inner border. 



Outside of the moraine a gravel plain about 6 miles in average width and in places 10 miles 

 in width is traversed for its entire length by Pigeon River. It is doubtful, however, if the 

 outwash from the Sturgis moraine was carried south of the river, the deposit on that side being 

 more probably formed as the ice border receded down the slope from the Lagrange moraine 

 to the river. A portion of the plain north of the river may also have been built up during the 

 recession to the position held by the Sturgis moraine. This interpretation is supported by 

 numerous basins far out in the gravel plain and by the presence of considerable coarse material 

 at distances to which it could scarcely have been carried by direct discharge from the moraine. 



The possibility of submarginal deposition of some of the gravel and sand should also be 

 considered, for in places a coating of bowldery material has apparently been let down by the 

 melting of the overhanging ice. Such material is especially noticeable in northeastern Lagrange 

 County in a reentrant between the Saginaw and Huron-Erie lobes east of a line running from 

 Lexington to Mongo. 



Generally speaking, the coarsest material lies in a narrow strip along the front of the moraine, 

 and within 2 miles from the edge it has given place to sand or very fine gravel. The descent 



