646 As Ch PEALE 
In the table already given, of the species listed in the column 
under “Denver Basin and Eastern Colorado,” more than half the 
number came from the very summit of the formation where there 
is no admixture of Pierre forms. Curiously enough, too, the list 
for the beds below the Judith River in Dr. Stanton’s section on 
east side of Cow Creek (see pp. 642-43) suggests no mingling of 
Pierre and Fox Hills forms, such as is so clearly shown in the 
collections made on the Yellowstone River about 150 miles above 
its mouth... Whether this indicates a condition in the Judith 
basin similar to that noted by Eldridge at Golden will have to be 
left to the result of future careful study of the Fox Hills outcrops. 
It is more than likely, however, that, as stated by Professor Meek: 
“These beds underlying the brackish-water lignite [Judith River] 
beds form an upper member of the Fox Hills group.” 
The mingling of the Fox Hills and Pierre faunas has been noted, 
but to a more limited extent, also in the Dakotas where, however, 
as we have indicated, the entire thickness of the Fox Hills is not 
seen. Indeed, it is questionable whether a full development of the 
formation occurs anywhere in this area. At the top of the Fox 
Hills sandstone, which has a marine fauna, Dr. Stanton found a 
thin and widely distributed bed with a brackish-water fauna which 
he regards as belonging to the Fox Hills rather than to the over- 
lying Lance formation, an interpretation that is not in accord with 
the views of the field geologists studying the area, who placed it 
immediately above the unconformity which marks the contact of 
the Lance on the Fox Hills. Similar brackish-water faunas are 
found, according to Dr. Stanton, wherever the Judith River forma- 
tion is found “intercalated in the upper and lower portions of the 
formation.’”’4 This occurrence, just referred to as at the base of 
the Lance formation, is on the line of the unconformity which, 
t Report U.S. Geol Surv. Terr., TX (1876), p. Xxxiv. 
2 [bid., p. XXXVI. 
3 Amer. Jour. Sci., XXX (September, 1910), 178. 
4 Bull. U.S. Geol. Surv., No. 257, p. 120. 
The entire quotation is: ‘‘The brackish fauna has a wide geographic distribu" 
tion occurring in practically every area in which the Judith River formation is found, 
but it is confined to thin beds intercalated in the upper and lower portions of the 
formation.” 
