504 
Buell—Boivlder Trains. 
Others found further south in the north half of the townships 
of Cottage Grove, Blooming Grove, Fitchburg and Verona were 
doubtless brought westward by the same drift movement as the 
last, but were probably redistributed by the later drift move¬ 
ments. 
Amount of material .—The amount of material noted within 
this area is comparatively small as would be inferred from the 
general concealment of its drift beneath the .detritus of later de¬ 
posits. In the localities described within the proximal portion 
of the trains about ten cords of quartzites were observed. Over 
the medial and marginal portions of the train a summary of 
the whole material noted on a surface exceeding twelve town¬ 
ships in area aggregates less than one-half of a cord. Yet it 
includes the actual enumeration of some hundreds of fragments 
of undoubted Waterloo origin, so distributed as to define a sym¬ 
metrical bowlder fan whose outlines are in exact correspondence 
with a distribution along lines radially divergent, which may 
reasonably be referred to the marginal action of an ice lobe 
whose axis lay somewhere in the line of the Lake Michigan basin. 
Correlation .—A correlation of this bowlder distribution with 
the thin, marginal drift deposit which has already been referred 
to in the description of the southwestward train is natural and 
supported by facts apparently conclusive. Among the lime¬ 
stone fragments which abound in certain portions of this mar¬ 
ginal drift, fossils from the Niagara and water-lime formations 
of the area adjacent to Lake Michigan are of frequent occur¬ 
rence which demonstrate that this drift was laid down along the 
margin of an ice sheet which crossed the area from the lake 
basin. This distribution of Niagara and Devonian fossils was 
along lines parallel with the bowlder belt just outlined and both 
belong apparently to the earliest incursion of the glacial ice 
across this region. 
CORRELATION OF DATA WITH PHENOMENA IN ADJACENT AREAS. 
Naturally the discovery of the complexity of features of drift 
phenomena shown in this limited district has led to much labor 
in the attempt to correlate these successive phases of drift 
movement with determinations made elsewhere. 
