512 TRANS. OF THE ACAD. OF SCIENCE. 



If they prove to be Permian, it shows the prophetic power of 

 those making it ; and if it proves not to be so, it will soon be 

 forgotten. 



That this was the interpretation they themselves put upon 

 it, is proved by their paper on these same fossils from the 

 Black Hills, published March 2d, 1858. In this section of 

 the Black Hills, they put the Potsdam and Carboniferous rocks, 

 but no Permian. They not only leave these rocks out of the 

 Permian, but actually place them in the Carboniferous, and 

 below the middle of that system.* And this is the interpre- 

 tation they themselves put upon this record six weeks after 

 it is made. They declare these fossils Carboniferous rather 

 than Permian. But four months later, they revise this sec- 

 tion! and change these rocks (E. and F. of section) to the 

 Permian, with a statement showing they were in doubt when 

 this record was made, or afterwards. 



These two letters to Maj. Hawn, above quoted, and this 

 record in the Smithsonian Institute, are the strongest proofs 

 yet adduced that Mr. Meek, or Dr. Hayden, had discovered 

 the Permian before I announced the fact, and these most pos- 

 itively prove that they were not fully satisfied whether these 

 fossils were " Permian or Carboniferous or Jurassic." They 

 rather thought they were Permian, at times, but seemed un- 

 willing to risk an announcement. 



On the 2d of March, 1858, J they read a paper before the 

 Albany Institute, with this caption : " Description of New 

 Organic Remains from North-Eastern Kansas, indi- 

 cating the Existence of Permian Rocks." 



This is called an announcement of a discovery; but it is 

 simply a declaration that it may become a discovery, and it 

 is probable the authors now so consider it, since they insist 

 on calling rocks in Kansas Carboniferous, which contain 

 nearly or quite all of the species described in this paper. In 

 their opinion, therefore, these fossils still merely indicate Per- 

 mian Rocks, and do not prove them to be such. And this is 

 proved to be the interpretation they wished to be put upon 

 it by their letter to Prof. Leidy, read, by their request, be- 

 fore the Academy of Natural Science, at Philadelphia, on 

 the very day this paper was read before the Albany Institute. 



The officers of the Academy so understood it as proved by 

 the record then made. A " letter * * * indicating 

 the probable existence of Permian^ Rocks." This is very 



*See Amer. Jour., July, 1867, p. 38. 



t Proc. Acad. Nat. Sci. Phil., 18G8,p. 144. 



\ Ei^lit days after my announcement was made in the St. Louis Acad- 

 emy of Science. (See Trans. Feb. 22, 1858.) 



If Proc. Acad. Nat. Sci. Phila., 1858, March 2. 



