576 The American Geologist. june, 1893 
In 1891, I traveled the same route followed by professor Mar- 
<30u, and when I reached the locality found that the mountain 
marked Big Tueumcari on Marcou's map is now called Mount 
Revuelto, and his Little Tueumcari is called Big Tueumcari, and 
the name Little Tueumcari is now applied to the small mountain 
between his Big and Little Tueumcari. 
The question ver}- naturall}- arose as to which butte was really 
■entitled to the name Big Tueumcari, the Cerro de Tueumcari of 
the first travelers. After looking into the matter as closely as my 
facilities admitted, I concluded that from some cause imknownto 
me, Marcou was in error, and so stated in my report and made my 
map to correspond with the facts as I understood them. I did not 
know Prof. Marcou's reasons for applying the names as he had, 
and did not assign an}' reason why I thought a mistake had been 
made b}' him. 
In the American Geologist, Dec. ,1892, in a review of my re- 
port, Prof. Marcou contends for the correctness of his designation, 
saj-ing, " The map of Mr. Cummins in the Third Ann. Rep. Geol. 
Surve}' of Texas, is at variance with the three first maps published 
and according to the right of priorit}' cannot be used for geograph- 
ical names of the Tueumcari mesa. ' 
It is due to Prof. Marcou and no less to m3self for me to make 
-a statement of the reasons whj^ I believed him to be mistaken in 
the application of the names. 
A word in regard to priority as I understand it : Had Prof. 
Marcou and partj^ been the first explorers through the country 
and had they found a number of buttes and designated an}- one 
-of them by a certain name and given its position on a map so 
that it could be identified \>y later travelers, he then could have 
claimed priority. But if he went into a country where others had 
been before him and where a peculiar butte had previousl}' been ob- 
served and named and where such a minute description of it had been 
given as to enable others who visited the same locality later to iden- 
tify it by the description, then the claim for priority would not be 
available for any map he might publish that did not agree with 
the previous designation. It was upon the ver}' ground of priority 
that I thought Prof. Marcou was wrong in his designation. 
Prof. Marcou can maintain his right to priorit}' to the name 
" P3'ramid mount " for one of the buttes in that vicinit}- because 
he gave that name to a hitherto unnamed hill. But Prof. Marcou 
