26 W. Cross — Post- La ramie Deposits of Colorado. 



Since then the species has been repeatedly collected from the 

 same beds and has also been detected at Black Bntte, Wyom- 

 ing-. 



That portion of the Hay den map representing the area to 

 the westward from the Animas River is based upon the work 

 of Mr. TV 7 . H. Holmes. In describing the series called the 

 Laramie, to which the strata observed by Mr. Stanton evi- 

 dently belong, Mr. Holmes usually refers to them as composed 

 of brown sandstones, shales, and dark colored cla} 7 s. In the 

 section on the La Plata River* he assigns a thickness of 800 

 feet to the " Puerco marls " of Pilion mesa which overlie 

 them, and 1120 feet to the coal-measure rocks below, which 

 are called Fox Hills. Through the kindness of Mr. Llolmes I 

 have been allowed to examine his original field notes in this 

 area, and find that the general resemblance of these " Lara- 

 mie " strata to those at Table Mountain near Golden was 

 recorded. There is, however, no definite evidence in these 

 notes to confirm the generalization suggested by Mr. Stanton's 

 observations that the strata between the '' Puerco marls" and 

 the coal-measures, west of the Animas River, are equivalents 

 of the Denver beds, although the strata noted by him cer- 

 tainly occur in that part of the section. 



In an article entitled : " The relations of the Puerco and 

 Laramie deposits"'!' Professor E. D. Cope states that ac- 

 cording to the observations of Mr. David Baldwin " the 

 Laramie beds succeed [the Puerco] downward, conformably 

 it is thought by Mr. Baldwin ; and have a thickness of 2,000 

 feet at Animas City, New Mexico. [?] They rest on Fox Hills 

 marine Cretaceous of less thickness. A few fossils sent from 

 time to time by Mr. Baldwin identify the Laramie. This is 

 especially done by the teeth of the dinosaurian genus Dys- 

 ganus Cope, which is restricted to the Laramie formation 

 everywhere. Also by the presence of the genera Lcelaps and 

 Diclonius, which in like manner do not extend upward into 

 the Puerco beds. The Lcelaps is principally represented by 

 teeth, which resemble those of the L. incrassatus Cope, more 

 than those of any other species .-...." " The Dysganus 

 agrees with the J), encausius Cope, which, with the Lcelaps 

 incrassatus, was described from specimens from the Upper 

 Missouri." 



In recent " Notes on the Dinosauria of the Laramie";}: 

 Professor Cope describes a new Dinosaur, Pteropelyx " found 

 near Cow Island, Montana, on the Upper Missouri, in 1876." 

 " The genus Pteropelyx displays characters between the 



* Ninth Ann. Eep. U. S. G. & G. S. 1875, p. 248. 

 f American Naturalist, vol xix, p. 985, 1885. 

 % American Naturalist, vol. xxiii, p. 904, 18S9. 



