The Mesozoic Series of New Mexico. — Marcou. 227 
and Arizona, the critics and strictures of my adversaries can 
not be taken seriously into consideration, having no basis to 
rest upon, either paliieontologically, lithologically or strati- 
graphically. 
Instead of improving my classification of the American 
Mesozoic series of 1853 and contributing to the progress of 
American geology all the efforts of my critics during the last 
thirty-six years have been directed to prevent its acceptance. 
They have failed to give a single new fact, only mixing the 
series of Mesozoic strata in a hopeless mass of confusion and 
errors ; and by their obstruction preventing the acceptance of 
truth and misleading the geologists who have trusted them. 
I am glad to say that a new generation of young observers 
has at last come to the front ; and that already the Necomian 
has been signalized on vast surfaces of Texas and in southern 
Kansas ; the Jurassic is recognized in the Tucumcari area and 
western New Mexico; the Trias is extended south and north 
of my line of travels by the 35th parallel; and finally the 
Dyas (Permian) of Topofki creek has been explored again and 
recognized as such, and its extension north into Kansas is 
also admitted. 
PosT-scRiPTUM. — Two srrors in the printing of the first part of my 
paper require explanation. 
1. At p. 162 the designations given at the left hand of the section of 
Pyramid Mount by Mr. James Hall ought to show that the bracket 
under the words: "corresponding to Nebraska section No. 1," does 
not stop at division A of the upper Keuper, but goes indefinitely lower 
down, as it is printed in the Mcrican boundary line, vol. i, p. 135; for 
Mr. Hall incloses ia his Nebraska section No. 1, not only two-thirds of 
my Jurassic system, but also the whole Trias and the whole Dyas. 
2. At p. 159 the editor says in a foot note, in regard to my speci- 
mens placed without my consent or even knowledge in (he hands of 
Mr. James Hall: "They were placed in his hands by order of the 
chief of engineers, through Mr. W. P. Blake." The chief of engineers 
had absolutely nothing to do with the whole matter. Here are the 
facts. 
Obliged by bad health to go to Europe, by doctor's order, I begged 
leave of absence from Capt. A. W. Whipple, chief of the explorations 
by the 35th parallel, my direct and only chief, who acceded at once. 
Almost at the last minute, when I was on the point of putting my foot 
on the deck of a Cunard steamer, I was ordered by Jetterson Davis to 
remain in the United States, or to give up my notes. It was materiallv 
impossible to obey either alternative. After my r.rrival in the Jura 
mountains, I surrendered my note-books and specimens to the secre- 
