258 
Buell—Geology of the Waterloo Quartzite Area. 
been subjected was first pointed out to me by Prof. Van Hise, 
and to him is due the suggestion that the schistosity developed 
in these original elastics would be found to be a valuable means 
for the discrimination of 1 his rock from other quartzites and 
its identification in the glacial drift'. 
My approach to the subject has been from the side of 
the relations of these quartzites to glacial phenomena, 
being interested in them chiefly as points of origin of 
bowlder material which is disseminated through the glacial 
drift over a considerable area to the south, southwest 
and west of the ledges. In tracing out this dis¬ 
tribution in has been found necessary to enter somewhat 
minutely into the geological relations of the series and to work 
out the structural features of the quartzite itself, these points 
being found essential in the consideration of the quesfions of 
glacial distribution. In this paper are presented only the re¬ 
sults of these studies upon the constitution and structure of 
the rock forming the ledge exposures, but with the object in 
mind of subsequently using this knowledge as a substantial 
basis for the working out of their relations to the more recent 
stages of geological history. 
FIELD NOTES. 
General Geological Relations —The area including these ex¬ 
posures lies about twenty-five miles east of Madison in the 
southern part of Dodge county and in the northwestern town¬ 
ship of Jefferson county. The outcrops all lie in a broad erosion 
basin formed from the layers of the St. Peters sandstones and 
the adjacent limestones. This basin is occupied superficially 
by broad marsh areas and is drained by the sluggish Crawfish 
river and its tributaries. The ledges therefore occupy a lower 
position than the drift-covered limestone ridges in the vicinity. 
The territory outlined by the exposures extends for about 
twelve miles in a direction west-southwest from its initial area 
to the northeast, and the southwest exposure lies about six 
miles from the opposite margin of the field. The three mar¬ 
ginal areas may be considered as outlining a rude crescent 
within whose cusps the fourth area is included. 
