84 Wisconsin Academy of Sciences^ Arts, and Letters. 
case became even worse confounded when Keyes^^ a few months 
ago made the St. Lawrence in its typical exposure in Minnesota the 
same as the Oneota and the Jordan sandstone the same as the 
New Richmond sandstone, renamed the Franconia (Albin shale), 
also the typical St. Lawrence (Allamakee dol.), and proposed the 
name Waukon sandstone for what Hall, Sardeson and Norton had 
called Jordan. 
Considering all this confusion—nomenclatural and stratigraphic 
—and wishing at the same time to preserve the credit really due 
to N. H. Winchell for naming two Cambrian horizons that are 
well marked both lithologically and faunally not only in Minne¬ 
sota but also in the adjoining states of Wisconsin and Iowa, some 
radical changes in names and in the definition and correlation of 
the concerned stratigraphic units seem necessary. After thorough 
investigation of the facts and much thought the best and only just 
solution of the various difficulties and issues seems to be the one 
here followed and in part newly proposed: namely 
(1) The restriction of the name Jordan sandstone to the wholly 
unfossiliferous, probably continental deposit of usually light gray¬ 
ish sandstone which occurs at Jordan, Minn., and is elsewhere in 
the Mississippi Valley easily recognized by its lithologic character 
and its position in the section between the top of the fossiliferous 
marine Norwalk sandstone member of the underlying formation 
and the more or less unconformable base of the often similarly 
sandy initial deposit of the succeeding Lower or Upper Ozarkian 
formation. 
(2) The restriction of the term St. Lawrence, in the original 
form of St. Lawrence limestone and not St. Lawrence formation, 
to the well-characterized and widely recognizable calcareous zone 
to which this term was originally applied by Winchell and to 
which it was again confined by him in 1888. 
(3) The proposal of a new name, the one chosen being Trem¬ 
pealeau formation, for the formation to which Ulrich in 1914 ap¬ 
plied the term St. Lawrence formation and of which the typical 
St. Lawrence limestone usually constitutes the basal member. The 
Trempealeau thus embraces the beds between the top of the Fran¬ 
conia formation and the base of the true Jordan sandstone. 
^ Keyes, Charles, Terranal differentiation of Iowa Cambric succession. Pan-Ameri¬ 
can Geologist, vol. 38, 1922, pp. 313—326. 
