I 
Art. IX.] Herrick-Johnson, Geology of the Albuquerque Sheet. 201 
necessary to divide the distance when it was actually measured. 
The lower beds of the red series Professor Cope refers to 
the Trias and reports that they are of fresh-water origin as they 
contain Unios and saurian remains. It may be doubted if the 
Unios actually came from the beds in question. If they did, 
a curious light may be thrown upon the occurrence of the cop- 
per so constantly found in this part of the series. The varie- 
gated beds of marl and sandstone are thus separated from the 
sands immediately beneath the anhydride, though there seems 
to be no special reason for such separation. 
Professor Cope also mentions the fact that the Jurassic 
beds contain conglomerate lime strata and copper, all of which 
facts induce us to believe that he had actually in mind our lower 
red-bed division. It would then be convenient to use the gyp- 
sum horizon as the upper limit of the Triassic but this leaves us 
in doubt as to the lower limit and as to the place of the Permian. 
Paleontology of the Cretaceous. 
The purpose of the following lisP is to serve as a running 
commentary on the plates accompanying this paper. It would 
be impossible at this stage of our study to present an adequate 
idea of the richness of the fauna of the upper Cretaceous and 
it would be presumptious to attempt even a full description of 
the collections already made without the means of broader 
comparison than we have at present. Nevertheless itds necessary 
to afford the student an opportunity to verify so far as possible 
the conclusions to which we have come and to supply the means 
of checking this part of the work. Several species which seem 
important as determinants of the several horizons have been 
collected and found undescribed so far as can be told at present. 
In a few cases new names have been proposed for these in order 
to facilitate reference though we should have preferred to defer 
the paleontological work till greater progress has been made. 
For those whose chief interest in geology is economic it is 
1 The assistance of Mr. H. O. Brooks in the preparation of this paper re- 
quires special recognition. 
