126 Trans. Acad. Sci. of St. Louis. 



series of the Carbonic section in the Rio Grande region 

 I have lately discussed at length. 6 The Bed-beds of 

 Kansas and the southern Rocky Mountains I have also 

 considered in some detail. 7 It suffices here merely to 

 note, by way of explanation, that in New Mexico there 

 are present three great groups of red-beds: One, the 

 Bernalillo Red-beds, in the Maderan series, the true Cimar- 

 ronian Red-beds, and the Triassic Red-beds. Each of 

 these red-beds sections has a thickness of about 1000 feet ; 

 and in some localities in New Mexico all three of them 

 appear superposed upon one another, forming a contin- 

 uous "Red-beds" sequence. 



The exact stratigraphic level of the Guadalupan series 

 is a subject that is now demanding critical attention. My 

 own observations, which are mainly stratigraphical in 

 character, point to a superior position of the Cimarron- 

 ian Red-beds, with reference to the Guadalupan division. 

 Girty, 8 depending largely upon paleontologic deduction, 

 is inclined to give the Cimarronian an inferior situation, 

 notwithstanding the fact that the red-beds are almost 

 devoid of organic remains. Thus this author is forced 

 to make the Cimarronian red shales an exact equivalent 

 of the Hueco limestones (Maderan-Manzanan series) of 

 the west Texas section. Insofar as there is any strati- 

 graphic evidence adduced for this conclusion the author 

 seems to be influenced by certain brief notes published 

 by Graton and Gordon. 9 From impressions gained by 

 the latter on the east side of the Rio Grande area these 

 authors seem to regard all of the red-beds of this valley 

 as belonging to the Bernalillo shales division (Maderan) 

 and report that above these red shales occurs a thick 

 black limestone lithologically similar to the Hueco lime- 

 stone which, in the Guadalupe mountains, immediately 

 underlies the Guadalupan series. This may be the cor- 



6 Jour. Geol. 14:147-154. 1906. 

 7 Proc. Iowa Acad. Sci. 15:143-144. 1909. 

 S U. S. Geol. Surv. Prof. Pap. 58:48. 1908. 

 9 Jour. Geol. 15:805. 1906. 



