126 Trans. Acad. Sci. of St. Louis. 
series of the Carbonic section in the Rio Grande region 
I have lately discussed at length® The Red-beds of 
Kansas and the southern Rocky Mountains I have also 
considered in some detail.‘ 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,’ 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.® 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. 
™Proc. Iowa Acad. Sci. 15:143-144. 1909. 
5’U. S. Geol. Surv. Prof. Pap. 58:48. 1908. 
® Jour. Geol. 15:805. 1906. 
