line > O-CAbEM Dr CRETACEOUS, DEPOSITS IN SOUTH- 
EASTERN MINNESOTA. 
THE extent of Cretaceous formations in Minnesota has not 
yet been exactly determined. Small areas of the Cretaceous 
are known to be extant in several places and also large areas 
are believed to lie hidden under the drift in the western half of 
the state, adjacent to or continuous with the Cretaceous forma- 
tions which occur in North.and South Dakotaand Iowa. Inthe 
region where large extent of Cretaceous is thought to exist in 
Minnesota, the glacial drift is very deep and the underlying 
formations are little, or not at all, accessible. In other regions 
where there is generally less drift, there is not much Cretaceous 
deposit. A few isolated areas only are reported to be Cretaceous- 
covered and these alone attest whether or not the Cretaceous 
deposits to the westward of Minnesota had once extended quite 
continuously eastward in the state to or beyond the central 
portions, as some geologists have thought. As far as has been 
ascertained, all known outcrops might well belong to local or 
even inland deposits. Again, whatever its extent, the Creta- 
ceous now lies, when present, always immediately beneath the 
glacial drift and in this position it might presumably be found 
strongly eroded, and, therefore, we not only do not know the 
original extent of Cretaceous sedimentary deposits in Minnesota 
but also we cannot safely predict how much of that unknown 
quantity might now be extant. 
The known extent of the Cretaceous in Minnesota is very 
small, while the sometimes estimated extent is very large. 
This statement may be well illustrated by reference to the final 
reports of the Minnesota Geological Survey, in which the maps 
of the several counties in volumes one and two, represent a few 
scattered spots of known Cretaceous, while the map of the 
state, in volume three, which is constructed from the same data 
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