WISCONSIN DRIFT BOEDER. 83 



lead down valleys that traverse this district properly belong to the moraines in which they 

 head. The gravel and sand seems to have been deposited in large part after the ice sheet had 

 withdrawn from this district. Some of the larger and steeper knolls contain gravel deposits 

 and the eskers are composed mainly of gravel, but except in these surface gravel is rare. Beds 

 of sand and gravel incorporated in the till are of small extent. 



ST. OMAR-HOPE UNDULATING STRIP. 



A strip of undulating drift about 15 miles long and 2 miles wide leads from near St. Omar 

 in northwestern Decatur County southwestward across southeastern Shelby County to the 

 village of Hope in Bartholomew County. It is crossed by Flat Rock Creek in Shelby County. 

 The portion on the north side of the creek includes sharp knolls 25 to 30 feet high. South of the 

 creek these are rare, but the wavy surface puts the strip in contrast with the flat tracts on 

 either side. 



Just outside this strip near the village of Adams a kame or gravel knoll, which is the most 

 prominent glacial feature in Decatur County, rises 60 feet or more above the surrounding 

 plain. Though composed largely of gravel, it has a coating of till several feet thick. The Bur- 

 ney esker, discussed below, also lies just outside this undulating strip. 



BURNEY ESKER. 



The Burney esker northwest of Burney in western Decatur County was noted and 

 described by Elrod 1 under the name "hogback." It extends southward about 2 miles from 

 sec. 5, T. 10 N., R. 8 E., into the northeast part of sec. 17. Clifty Creek crosses it in the south- 

 east quarter of sec. 5. The esker ranges from 10 to 25 feet in height and is single, except in sec. 

 8, where it is double for half a mile, inclosing a swampy tract about 100 yards wide. It is not 

 accompanied by a channel or esker trough, nor does it have a fan or delta at its southern end. 



The esker consists of very coarse material, its northern portion including bowlderets and 

 cobblestones as well as gravel, and its southern portion gravel of medium coarseness. The 

 surface deposits are on the whole coarser than the basal ones, which include considerable sand. 

 The pebbles, both coarse and fine, are largely limestone derived apparently from the rock 

 formations of the region. There is a tendency to bedding in conformity with the upper sur- 

 face, with a dip down the slope from the crest. Such bedding is explained, on the ice-tunnel 

 hypothesis, by the melting of the supporting ice from beneath the upper beds at the sides of 

 the tunnel which allows them to drop down over the lower beds. 



MALTA UNDULATING STRIP. 



A gently undulating tract about 15 miles in length and 1 to 3 miles in width leads from 

 near Malta hi Putnam County eastward to Reno in Hendricks County, and thence southeast- 

 ward past Stilesville. Its knolls are commonly but 10 to 15 feet high and are closely clustered 

 in but few places, there being usually but a few knolls to a square mile. This undulating strip 

 may mark the position of the ice margin at a brief halt in its withdrawal from this region. 



MALTA ESKER. 



The Malta esker is a ridge about 3 miles in length, which sets in on the west bluff of Clear 

 Creek in sec. 23, T. 15 N., R. 3 W., and runs south-southwest along the edge of the valley and 

 across sec. 27 to Warford Fork in sec. 34, where it makes an abrupt turn to east of south and 

 ends at the south side of the vaUey of Warford Fork in a cluster of gravel knolls in the edge 

 of the Malta undulating belt, about a mile north of Malta. Clear Creek crosses it through a gap 

 about a mile south of its beginning in sec. 23. 



For about a mile at the north end the esker consists of a string of low gravelly ridges 

 scarcely 10 feet high, with gaps of considerable width. South of Clear Creek it is more promi- 

 nent and is nearly continuous to Warford Fork, with a height of 10 to 30 feet and a width of 

 50 to 75 yards. It does not occupy a well-defined trough or channel but has its base at the 

 level of the bordering till plain. 



1 Twelfth Ann. Eept. Indiana Geol. Survey, [or 1882, pp. 143-144. 



