STRATIGRAPHIC POSITION OF JUDITH RIVER FORMATION 755 
SUMMARY AND CONCLUSIONS 
The Judith River formation was named and considered by Dr. 
F. V. Hayden to be of Tertiary age and, from that time (1855) to 
1903, every geologist who studied the beds coincided in the main 
with his views. A list of these geologists who studied the beds in 
the field is as follows: F. B. Meek, E. D. Cope, C. A. White, 
Walter H. Weed, L. F. Ward, George M. Dawson, G. B. Grinnell, 
Ed. S. Dana, and T. W. Stanton. Not until 1903 was there any 
question as to their position nor much discussion as to their age, 
except by the vertebrate paleontologists. In this year after a study 
in the folded and faulted region surrounding the Bearpaw Moun- 
tains in Montana, Stanton and Hatcher traced the outcrops noted 
near Havre on the northeast side of the mountains up Milk River, 
across the international boundary to Pakowki Coulee and correctly 
correlated the beds exposed at Havre with the Belly River beds 
already identified on Milk River by the Canadian geologists, but 
they incorrectly correlated these beds with the Judith River forma- 
tion exposed mainly between the Bearpaw Mountains and the 
Missouri River, confusing the two formations as the Canadian 
geologist had previously done. ‘These formations were the Judith 
River beds overlying the Pierre and the Belly River series lying 
below the Pierre shales. This confusion as to position, as noted, 
had occurred also in the Canadian outcrops and was straightened 
out by McConnell and Tyrrell. Stanton and Hatcher were led into 
the same error also on Fish Creek south of the Musselshell River 
and on Willow Creek north of the same river in Montana, as was 
very evident to us when we revisited this area in 1911. Our first 
conclusion, therefore, is that the Judith River beds and the Belly 
River series, although both of fresh-water origin and lithologically 
very similar, are entirely distinct from each other, occupying 
stratigraphical positions separated by 1,000 feet or more of marine 
sandstones and shales. 
The sandstones and sandy shales immediately underlying the 
typical Judith River beds are of marine origin and contain a fauna 
which Dr. Stanton says has long been considered a “typical Fox 
Hills” fauna. In addition to this fauna we found Halymenites 
major, a characteristic plant of the Fox Hills formation, throughout 
