IS The Americg.il Geologist. January, 1864 
geological foundation that they show a familiarity with geo- 
logical science. The most of these geological papers relate 
to Wisconsin. In his first Ohio paper he makes the earliest 
recorded observation of petroleum filling the cavities in lime- 
stone, a fact which was extensively discussed later by Dr. T. 
Sterry Hunt and by Alex. Winchell, both of these geologists 
regarding it as indicative of the origin of the large reservoirs 
of petroleum which have been discovered later.* In his paper 
on the primitive boulders of Ohio (in conjunction with his 
brother Darius) he gives facts which show that they increase 
both in number and in size, from the Ohio river northward 
as far as the shore of lake Erie, and concludes that they 
must have had their origin in Canada; and inclines to con- 
sider their transportation due to some great flood acting in a 
southward direction. This was before Agassiz had an- 
nounced the results of his Alpine studies on glaciers, and 
was an important original contribution to the geology of the 
drift. In his paper on certain lacustrine deposits likely to 
be. confounded with the drift, he makes an important dis- 
tinction between the stratified fine clays, like those from 
which the cream-colored brick are made at Milwaukee, and 
the true pebbly and stony drift clays underlying. The finely 
laminated clays he ascribes to the action of the great lakes 
when they stood at a higher level. He notes the same clay 
between Detroit and Ypsilanti, Mich., at which latter point 
he makes first mention of the ancient lake beach. This dis- 
tinction has been verified by extended observations about 
the great lakes. Prof. Chamberlin has carried it much 
further and ascribes to lacustrine origin some of the pebbly 
clays which seem to be a phase of the laminated brick clays. 
'•Lapham's Wisconsin," is a duodecimo volume of 208 pages 
(second edition) and gives a general account of the Territory 
as then constituted. Wisconsin then contained that part of 
Minnesota east of the Mississippi river and south of the inter- 
national boundary as far west as a line running north from 
the source of the Mississippi. This limitation of its territory 
and a similar reference to the source of the Mississippi in a 
*Hunt. Contributions to the chemical and geological History of 
Bitumens, and of pyroschists or carbonaceous shales. Am. Jour. Sci., 
(2) xxxv, p. 157. 
