260 
Buell—Geology of the Waterloo Quartzite Area. 
glomerate appears wherever the thin drift covering has been 
removed. It is first seen near the crest of the ridge and dis- 
plays a very coarse boulder bed of rounded, wave-worn quartz¬ 
ite blocks of three or four square yards area lying closely to¬ 
gether and imbedded in a matrix of finer quartzite and sand. 
As the formation is followed away from the ledges down the slope, 
the size of the quartzite blocks gradually decreases, until, on the 
bank of the river, a quarter mile distant from the out-crops, 
the conglomerate passes into a coarse friable sandstone. At cer¬ 
tain points the imbedded quartzites present deeply exfoliating 
surfaces indicating extensive weathering. 
This conglomerate appears at exposed points for half a mile 
along the north slope of this ridge and limited areas have been 
noted on the west side of the Portland area on Section 3, Water¬ 
loo township. No other exposures have been found in the district, 
though conglomerate bowlders have been seen in the drift in 
the vicinity of the Lake Mills outcrop. 
Quarry ledge, the largest single outcrop of the range, lies 
just south of the last area in the southeast quarter of Section 33. 
The ledge rises abruptly on its east side, its slope correspond¬ 
ing to the dip of the strata and its highest point having an 
elevation of forty-five feet above the marsh level. From this 
marginal crest the surface slopes gently to the southwest until 
its border disappears beneath the marsh. A thin drift over- 
lies the greater part of the ledge, but where this is removed 
the rock presents a gently undulating glacially planed surface. 
The strike and longer axis of this out-crop extends in a north¬ 
west-southeast direction from the center of the north line of 
the quarter section into Sections 3 and 4, Waterloo .township. 
Its length is one hundred and eighty rods, and its greatest 
breadth is eighty rods; its area is about fifty acres. 
A quarter mile east of this ledge is a high drift ridge that 
extends for two miles from the margin of the Crawfish on Section 
27, Portland township, into Sec. 3, Waterloo township. On the 
slope facing the quarry ledge a shoulder of rock cuts through the 
drift for nearly a half mile and on the other side of the hill is 
a low ledge which covers an area of ten acres. On the de¬ 
scending crest of this ridge half a mile southwest of the last 
