160 Mesozoic Series of Neio Mexico. — Marcou. 
If we compare this table with table I, we see that Mr. James 
Hall has placed in his Lower Cretaceous No. I=Dakota group, 
all the strata above the Carboniferous system, recognized by 
me in 1853 as belonging to the Neocomian, the Jurassic sys- 
tem, the Triassic system and the Dyassic (Permian) system; 
nullifying all the stratigraphy, the lithology, and what is worse, 
also the palaeontology. 
It is a mistake similar to that of placing 25,000 feet of pre- 
Potsdam strata, called Taconic system by Dr. Emmons, in 
parallelism with the Hudson River group and the Oneida con- 
glomerate ; Mr. Hall going so far as to use the same expres- 
sions of "unquestionable," "unequivocal,'"appliedinboth cases 
to fossils and series of strata, which he tried to suppress. And 
in order that no equivocal understanding may be applied to 
his classification, he has colored on a geological map entitled : 
"Map illustrating the general geological features of the country 
west of the Mississippi river" all the road explored by me from 
Delaware ridge (Indian territory) to the Tucumcari area (New 
Mexico) as covered only by the Dakota group or Lower Cre- 
taceous No. I, which singularly enough does not exist there in 
a single spot. 
That classification has been accepted, defended and used in 
papers, in manuals and in geological maps until 1887, by 
Messrs. J. D. Dana,' Meek,- W. P. Blake,' the two brothers 
Drs. Shumard," C. H. Hitchcock,' R. H. Louhgridge "^ and W. 
J. McGee.' An extensive literature based on it exists, of which 
I give here only a small portion. 
The determination of my Mesozoic fossils b}' Mr. Hall has 
been accepted, defended and used in all the pahieontological 
papers, or stratigraphical papers in which lists of fossils have 
^ Arncr. Jr. Sci. vol. xxvi and xxvn, 1858-50. Manual of Geologij, 
etc. 
' Proceed. .\ead. Nat.Sci., Phihidelphia, 1857-60. 
■^ Amer. Jr. Sci., vol. xxii, 1856. Pacific railroad explorations, 4to 
edition, vol. iii, and vol. ii, 1856. 
^ Firat report of tJie geographical survey of Texas, 1850. Trans. Acad. 
Sci., St. Louis, 1860-61. " J partial report of the geology of western Texas, 
Austin, 1886, etc., etc. 
* Geological map of the United Stales, compiled for the 9th census, 
1872. Geological map of the United States and part of Canada, compiled 
for the Amer institute of mining engineers, 188G, etc. 
''Ninth census. Report on cotton production in the United States, 1884. 
■ ^fap of the United States e.vhibiting the present status of knowledge 
relatinq to the areal distribution of geologic groups, 1884. (Fifth Ann. Rep. 
U. S. Geol. sitrvey.) 
