PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER Ts, 
This member with its true Rhynchotrema, Rafinesquina, and large Sowerbyella 
is of about the same age as the preceding member and is correlated with part 
of the Kimmswick of Missouri and Curdsville of West Tennessee and Kentucky. 
Prosser formation.—The Ion member of the Decorah formation is overlain 
by rocks lithologically and faunally quite distinct from the underlying shales. 
The Prosser formation overlying the Ion member is thin-bedded limestone and 
calcareous shale abounding in fossils. The species occurring in this formation 
introduce new elements for the upper Mississippi Valley such as Vellamo, Platy- 
strophia, Furcitella scofieldi (Winchell and Schuchert). These indicate correla- 
tion with the Kimmswick of Missouri and the Sherman Fall of New York and 
Ontario, but these elements do not occur in the Appalachians. 
Obolellina parva (Whitfield) Philhedra depressa Cooper 
Parastrophina bernensis (Sardeson) Rostricellula acutiplicata Cooper 
P. rotundiformis Willard Rostricellula sp. 3 
The Salona of Virginia and Pennsylvania contain many Kimmswick elements 
such as the ball cystid Echinosphaerites, large Parastrophina, large Sowerbyella. 
Templeton and Willman (1952, p. 6 and fig. 3) propose the name Dunleith 
for the combined Prosser and Ion of Wisconsin and Illinois and split their 
new formation into 10 members. 
UPPER MISSISSIPPI VALLEY FORMATIONS NOT IN GENERAL USE 
Lowell Park member of Platteville formation.—This name was applied 
by Knappen (1926, p. 54) to interbedded gray and buff heavy-bedded limestone 
and coarse-grained, yellow-brown porous dolomites like the overlying Galena. 
The formation is 20 to 30 feet thick. It overlies the “blue” limestone and under- 
lies the Galena and thus forms the upper member of the Platteville. Brachiopods 
listed are: 
Leptaena charlottae Winchell and Schuchert Strophomena incurvata (Shepard) 
Orthis tricenaria Conrad S. trentonensis Winchell and Schuchert 
Rafinesquina minnesotensis (N. H. Winchell) 
Minneapolis limestone.—This was proposed by Sardeson for the basal bed 
of the Beloit formation or lower Platteville. (See Wilmarth, 1938, p. 1381.) 
Beloit dolomite formation.—This is another name proposed by Sardeson 
(1896) which includes the equivalents of the Decorah and Platteville. (See 
Wilmarth, 1938, p. 157.) 
MIDDLE MISSISSIPPI VALLEY 
In this part of the Valley the section, in ascending order, consists of the 
Buffalo River series, Rock Levee formation, Plattin group, Decorah formation, 
Auburn chert, and Kimmswick limestone. Some members of the Buffalo River 
series are well displayed in Ste. Genevieve County, Mo., and in the vicinity 
of Cape Girardeau. 
Buffalo River series (originally Big Buffalo series, but the name of the 
Big Buffalo River, after which the group is named, was changed by the Geo- 
