AGE OF THE AEAPAHOE AND DENVEB. 239 



"Descriptions of some vertebrate remains from the Fort Union beds of 

 Montana," 1 the localities and stratigraphical position of the strata yielding 

 these remains were very clearly given by Professor ( lope 2 in the next \ car. 

 and it then appeared that the "Judith River beds," one of the Local 

 divisions of Hayden's "Lignitic" series, was the immediate formation from 

 which the fossils were obtained. According to the personal communication 

 of Mr. J. B. Hatcher, nearly all of the forms described by Professor Marsh 

 "from the Laramie of Montana" were obtained by Mr. Hatcher in the same 

 series of strata in the Judith River region which contained the fossils 

 described by Professor Cope. Without reviewing in detail the literature 

 of these beds it is desired to point out the fact that the Judith River strata 

 mayperhaps represent the Arapahoe or some other post-Laramie formation, 

 and not the true Laramie of Colorado and Wyoming. 



The explorations of the Harden survey and other later examinations 

 of the Judith River and adjoining districts have shown a complex of some- 

 what variable sandstones, shales, clays, and lignites containing in various 

 horizons fresh and brackish water shells and the vertebrate fauna of Cope 

 and Marsh. Below this complex is the Fox Hills Cretaceous and above 

 it the Fort Union formation, the latter boundary not being as yet well 

 established. On account of stratigraphic relation to the Fox Hills, and 

 from the evidence of the faunas mentioned, the reference of these strata 

 to the Laramie has not previously been questioned, so far as the writer is 

 aware. 



Instead of reviewing past descriptions of the Judith River country 

 the following notes by Mr. T. W. Stanton, who visited the region in 1894 

 in company with Mr. W. H. Weed, are given with his permission. They 

 pertain only to the lower part of the series, but the main question under 

 discussion is as to the lower known limit of the Ceratops fauna. Mr. 

 Stanton gives the following description of the section near the mouth of 

 the Judith River: 



The freshwater Judith River beds are well exposed in bluffs ou Dog Creek, 4 or 

 5 miles from the mouth of Judith River, and also on the north side of the Missouri 

 within 3 or t miles of the same place. The section in this neighborhood shows about 



1 Proe. Acad. Nat. Sci., Phila., Vol. XXVIII, 1876, p. 248. 

 - Bull. U. S. G. an<l G. S., Vol. Ill, 1877, p. 565. 



