/ in- reus*- Allen Lapham. — Winchell. 19 
definition of the international boundary by the treaty between 
France and Great Britain in 1763, invested that mythical 
"source" with such importance that it became the goal of all 
northwestern explorers, an object of ambition worthy of the 
most costly and arduous search. Such it has remained almost 
to the present time. In this general account this territory is 
divided into four grand districts, viz : 1. The Primitive; 2. 
The Sandstone ; 3. The Mineral ; 4. The Limestone districts. 
The Mineral district is what is now known as the Lead and 
Zinc district of Wisconsin, in its southwestern portion. The 
other districts are sufficiently defined in their names. In the 
description of the limestone district he announces a generali- 
zation, based on the general geology, which, as it is not in 
keeping with some curious facts which he also admits, shows 
his reliance on the truths of geology. He argues that, as the 
limestone of the limestone district passes toward the south 
beneath the coal-bearing rocks of the state of Illinois, and is 
hence probably the Carboniferous limestone on which those 
rocks rest in that state, there can be no hope for the existence 
of coal within the state of Wisconsin. This important gener- 
alization, however, was confronted by the following statement 
which in the light of recent evidence going to show the for- 
mer existence of the Cretaceous in eastern Wisconsin, is at 
once a mark of Laphanfs sagacity in not allowing it to swerve 
him from a general truth, and apparently is a further con- 
firmation of the hypothesis of the eastern extension of the 
Cretaceous over a large area from which it is usually ex- 
cluded : 
Coal. — Small fragments of coal, associated with bituminous shale, or 
coal slate, have been found on the shore of Lake Michigan, at Milwau- 
kee and elsewhere ; and some indications of coal are said to exist in the 
vicinity of lake Winnebago. 
He also mentions petroleum, and bituminous matter found 
in the cavities of the eastern limestones in Wisconsin, and 
cites the reported existence of waterlime in the territory. He 
gives a list of the minerals known to occur in the territory, 
and a more or less detailed description of twenty-seven coun- 
ties. 
Dr. Lapham's contribution to the report of Foster and 
Whitney on the geology of the Lake Superior land district 
