The Mesozoic Series of New Mexico. — Marcou. 219 
marked as Jurassic -from Covero to Zuni. And professor Rob- 
ert T. Hill has recognized, in 1888, at the Little Tucumcari the 
Jurassic system, with its characteristic fossil the Gry])hcea 
dilatata var. Tucumcarii, saying in a printed circular : "The 
reaffirmation of the age of the Tucumcari section along the 
northwest corner of Texas to be uppermost Jurassic, as origi- 
nally described by Marcou." 
The only change made by Dr. Newberry in his classification 
of 1858, is that he has become convinced that the fossil plants 
of the coal of Moqui, which he called a "Jurassic florula," do 
not belong to the Jurassic system, for he says : "It is, how- 
ever, true at the present time (1876) that no Jurassic plants 
have been found on this continent;" showing once more 
how unreliable fossil plants are for the determination of the 
age of strata, and what degree of confidence may be placed in 
Dr. Newberry's palseobotanical conclusions. 
The resume of Dr. Newberry's exploration of 1859 contains 
a paragraph which I should not have written, notwithstanding 
the numerous provocations of my opponents ; but as it applies 
so well to the extraordinary classification they have chosen to 
make and to perpetuate by all means, as well for the Mesozoic 
series of New Mexico, the Indian territory and Texas, as for 
the Palfeozoic series of New York, Vermont and Canada, I 
shall quote it : "These unfortunate American geologists find 
to their confusion that the roof of their geological edifice was 
constructed before the foundation was laid" (Amer.Jour.Sci., 
XXVIII. p. 299, Sept. 1859). 
1863. Maecou. In an exploration of eastern Nebraska and 
western Iowa made during the autumn of 1863, I recognized : 
first, the Dyassic S3'stem at Nebraska City, extending farther 
north my discovery of the Magnesian limestone or Permian of 
Arizona and of Topofki creek of 1853 ["Une reconnoissance 
geologi(iue au Nebraska, Paris, 1864;" "Carbonformation und 
Dyas in Nebraska," von H. B. Geinitz, 4to, Dresden, 1866; 
and "LeDyas au Nebraska," Paris, 1867] ; and secondly the 
true White chalk, with chalk like the European white chalk 
of England and France, at Sioux City. The main object of 
my visit in Nebraska was to see the original locality of Black- 
bird Hill, given as typical by Meek and Hayden of their 
Dakota group or lower Cretaceous No. 1. I found dicotyledo- 
nous leaves at Tekama, at Blackbird hill and at Sioux City ; 
