ON THE STRATIGRAPHIC POSITION AND AGE OF THE 
JUDITH RIVER FORMATION 
AL CG. BEALE: 
For some years there has been a suspicion in the mind of the 
writer that perhaps, after all, the older geologists were correct in 
their views as to the position of the Judith River beds in their 
relation to the previously recognized, undisputed Fort Union 
formation, 1.e., that the Judith River beds were immediately below 
the Fort Union formation. This view was strengthened when, in 
1909, plants of undoubted Fort Union age were brought in from 
supposed ‘Judith River beds” on Big Sandy Creek, about fifty. 
miles northwest of the mouth of the Judith River, by members of 
the U.S. Geological Survey, and confirmed upon a careful study 
and review of the evidence furnished by stratigraphic, vertebrate, 
and invertebrate data as detailed by Stanton and Hatcher in their 
work? and by Dr. O. P. Hay’s paper ‘‘Where Do the Lance Creek 
(Ceratops) Beds Belong?”3 It is the purpose of the present paper 
to show that the Judith River beds are of Eocene-Tertiary age, and 
not of Belly River (Cretaceous) age, and are to be correlated with 
the Lower or somber portion of the Fort Union formation as 
defined and described by Knowlton,‘ now known as the Lance 
formation. 
Nearly forty years ago, or, to be more exact, in 1875,5 the writer, 
in attempting to correlate the Cretaceous and Tertiary formations 
in connection with work of the Hayden Survey in Colorado, took 
up the consideration of the Judith River beds, and among other 
™ Published by permission of the secretary of the Smithsonian Institution. 
2 Bull. U.S. Geol. Surv., No. 257, 1905. 
3 Proc. Indiana Acad. Sci., Twenty-fifth Anniversary Meeting, 1909. 
4 The “Stratigraphic relation and paleontology of the ‘Hell Creek beds,’ ‘Ceratops 
beds,’ and equivalents, and their relation to the Fort Union formation.”’—Proc. Wash. 
Acad. Sci., XI, No. 3, pp. 179-238. 
5 U.S. Geol. and Geog. Surv. Terr., 1874, Washington, 1875, pp 154, 155. 
53° 
