Correspondence. 317 
ProfessorHill has done a good work in giving more details ot" the Creta- 
ceous strata of Texas and in referring each subdivision to its proper posi- 
tion in the series. But the classification given by me between 185o-63, 
reported upon by de Verneuil liefore the French National Academy of 
Science and accepted by all the leaders of geological classification, was 
not changed by professor Hill, who has only developed the sub-divis- 
ions ; a work much wanted and which is very creditable to his skill and 
ability as a practical stratigraphist. 
In his "Check List," professor Hill continues to place his "Trinity 
divison" in the Lower Cretaceous or "Comanche series", and he still 
regards the fauna of the Trinity division as brackish {Amer. Geol., vol. 
V. No. 1, p. 62, January 1890.) instead of referring it to the Jurassic sys- 
tem and the fauna to a n}Hrine one. Both views are unacceptable for 
they are against fact; the fauna being entirely marine and l)eing com- 
posed of Upper Jurassic forms, without a single characteristic Creta- 
ceous animal in it. 
At p. 4 professor Hill confounds the young specimen of Gryphxa tu- 
cumcarii with the Gryph^a pitcheri, saying: "The same variety was 
beautifully figured in Marcou 1, as var tucumcarii.'^ I thought that 
the "endless confusion" was at an end ; but it seems not. I have never 
figured a Gryph;ea pitcheri as var. tucumcarii; the fig. 2, plate IV of my 
"Geology of North America," referred to by profes-sor Hill is a young 
individual, splendidly preserved of the Gryphx<idilatata var. tucumcarii 
of the Pyramid Mount section, Tucumcari area, taken by me in situ in 
the bed d which is full of Gryphwa tucumcarii. At p. 5, professor Hill 
says: "Gri/p/ia-'ap/^cAeri var. (Mcwmccin/, Marcou 1. See remarks on 
G. forniculata, White." There is nothing at G.forniculataSihovii&iiy of 
my Pyramid Mount fossils,and I have never published a 6rrj/p/ia;a under 
the name oiG. pitcher i\ar. hicwmcara jNiarcou ; it is certainly a mistake. 
The "preliminary check list" of profe.ssor Hill is a great improvement 
on the singularly incorrect lists published by B. F. Shumard, W. M. 
Gabb, F. B. Meek and Dr. C. A. White, and will be of great use to all 
))ractical geologists in their future investigations of the American 
Cretaceous system. 
As he says in his "Bibliography" p. 55, references to publications of 
first mention in the Texas region of fossil species are not complete as 
modern bibliographic standards require ; and it is certain that professor 
Hill's list may he extended easily and with great advantage as regards 
the discoveries of fossil species and their true stratigraphic meaning, 
more especially for the publications issued between 1853 and 18(53, but 
he reserves it as an addition to future editions. , 
26 March, 1S90, Cambridge, Mass. Jules Marcou. 
RECENT PUBLICATIONS. 
1. State and Government Reports. 
Forty-first annual report of the trustees of the state museum of 
natural history, for 1887, Albany, Bvo, 397 pp. 8 plates of fene8tellid;e. 
