■ Coal Measure Horizon in N. M. — Herrlck and Bejidrat. 237 
crodon carbonaria, Aviculopecten scalaris, and others which 
had been detected nowhere else in the territory, mingled with 
such forms as Chonetes mesoloba, Spirifer opima, and other 
species of an extended range within the Coal Measures. It 
would seem that an identity of physical conditions in widely 
separated areas of the same age might readily serve to collect 
local faunas of great similarity and with a large number of vi- 
carious species, but that these species should be identical in- 
dicates a larger continuity of the Coal Measure sea than had 
seemed to us probable. That the general conditions in New 
Mexico during the Coal Measure period were quite different 
from those existing in Ohio at the same period is evident from 
the entire absence of coal in the southwest. In spite of this dif- 
ference it appears that the shallow and protected bays were cap- 
able of sustaining a considerable fauna of delicate mollusks 
which were for the most part the same as those living in Ohio. 
The horizon at Flint Ridge in Ohio is near the top of the 
productive Coal Measures and has a few forms, such as Pro- 
ductus punctatus, that have not been found at so low a level in 
New Mexico. We subjoin a few notes on the two faun^ com- 
pared, but must reserve a critical study for a subsequent oppor- 
tunity. 
An inspection of the list will show that out of 34 species 
recognized 24 are also found at Flint Ridge, Ohio. No doubt 
a more extensive collection might modify the proportions, but 
the resemblance is so great that we may congratulate ourselves 
on having data for at least an approximate determination of the 
equivalence of the lower portion of our Carboniferous series as 
exposed in Bernalillo county in central New Mexico.* 
List of Fossils from the Sa/ulla Mountains of Neiv Mexico, 
found In a Band of Shale Supposed to Correspond to the 
Flint Ridge Shales of Ohio.\ 
♦Collections made since the above was written in Otero county in 
southern New Mexico indicate that several fossiliferous liorizons inter- 
vene at that place between the zone in ([uestion and the Buriin,t,non 
which forms a large formation below it. 
tThe species also represented at Flint Ridge are marked with an 
asterisk. 
