Ulrich—Paleozoic Systems in Wisconsin. 
77 
top of the Dresbach sandstone. Besides^ the succeeding Jordan 
sandstone is given a thickness of 200 feet and this of course drops 
the base of the Jordan far down toward the top of the Franconia. 
In fact it leaves between the Jordan and the Franconia only what 
would be required by the 30 feet or so of limy beds that constitute 
the typical St. Lawrence limestone. Moreover^ knowing most of 
the localities mentioned by them I am certain that not only the 
greater part of the shales but also some of the magnesian limestones 
which they correlate with the typical St. Lawrence are really in the 
Franconia. But all this is difficult to reconcile with their definite 
statement (p. 172) that the beds exposed at the type locality 
represent ‘ ^ the lower half of the formation. ^ ’ Evidently limy beds 
of the Franconia were confused with those at St. Lawrence. 
However erroneous some of the correlations of beds in the “St. 
Lawrence” of Hall and Sardeson’s 1895 paper may be the fact of 
greatest importance in this connection is the implied and partly 
carried out intention to expand the stratigraphic meaning of the 
term St. Lawrence. 
The first definite and unqualified change was made about 1910 
when the U. S. Geological Survey Committee on Geologic Names 
decided how the Cambrian and Lower Ordovician rocks in the 
Upper Mississippi Valley were to be divided and what names they 
should bear. These decisions appear in two Water Supply Papers, 
No, 256, by Hall, Meinzer, and Fuller, and No. 293 by Norton and 
others, published in 1911 and 1912 respectively. Now for the 
first time since 1888—-if we disregard the work of Hall and Sarde- 
son mentioned in the preceding paragraph—the St. Lawrence lime¬ 
stone becomes a formation and is increased in thickness from the 
preceding maximum of 30 feet to over 200 feet. This expansion 
was brought about mainly by incorporating the underlying Fran¬ 
conia sandstone which had been named in the meantime. No rea¬ 
son is given anywhere in these two papers for this unwarranted 
and really quite inexcusable proceeding. Even though it was not 
yet known that still another formation-—since described under the 
name Mazomanie sandstone—wedges in from the east between the 
base of the St. Lawrence limestone and the top of the Franconia, 
anyone well acquainted with the field relations of the concerned 
stratigraphic, faunal, and lithologic units could hardly have failed 
to recognize the thorough distinctness of the Franconia on the one 
hand and the beds above it on the other. The top also of this 
expanded St. Lawrence is an unnatural and often indefinite bound- 
