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Wisconsin State Agricultural Society. 
tinent. As this was the latest great geological change preceding 
the present, the existence of such a monument is necessarily of 
great interest to the world of science. All portions below this 
level were at the time submerged, and we are thus enabled to note, 
through the long ages, the several steps in the continental uplift, 
which, it is believed, acted with about uniform force throughout. 
The rocky surface of our present limestone hills, as we know from 
examination, was the flooring bed of this icy sea. Their polished 
tops, wherever the material was sufficiently hard and compact, fur¬ 
nish indubitable evidence of the agency that planed them to a level, 
marked them with scratches more durable than the graven art could 
have accomplished, and they now stand as silent witnesses of the 
mighty changes that time has since wrought. As we descend toward 
the sea, either eastward or toward the south, the successive ter¬ 
races met with attest the power, and mark the bounds of the reced¬ 
ing waters, from age to age, as they retired from the land. Nature 
has written her record of the past in characters not to be mistaken. 
Immediately following the conclusion of inter-continental de¬ 
pression, there came another era marked by what is known as the 
modified drift—a period of comparative repose—when the clays of 
that olden date were precipitated upon the bottom of the sea in 
the form of mud. About all that remains of this deposit is now 
found resting conformably upon the tops of such of our rock-ribbed 
hills as have withstood subsequent erosion. It has a variable thick¬ 
ness, which in this vicing may be approximately estimated at 
about ten feet. West of the Blue Mounds, in portions of the 
lead region not visited by the drift, heavy layers of clays are found, 
which may possibly be referred to the same period, as their level 
indicates submergence at the same time. In any event, these clay 
beds as now found in place may be considered the parent of the 
soils and subsoils of the State. At present, what remains of them 
in place, may be regarded as mere outliers, marking what was 
probably the first deposit of the kind within our geographical limits. 
All else is of a secondary origin, either derived from this original 
source or the result of decomposing rocky strata, and accumulated 
elements of vegetable and animal decay, mixed more or less with 
the finely-pulverized sands or pebbles of the original drift-formation. 
When the frozen sea retired, there came, in the course of time, a 
change of climate over all this region, which may possibly be ac- 
