XLVIII BULLETIN NO. 23, UNITED STATES NATIONAL MUSEUM. 



Mj^ belief is that we shall in the end have to ])nt the Old Eed Sandstone 6f England 

 in the same chapter as the upper or true English Silurian group. The Permian, Pom- 

 fret, or Magnesiau limestone series (the Zeckstein of the German) is physically better 

 related to the Triassic groups than to the Carboniferous, though the fossils seemed 

 to point the other way. 



I am now seventy-one years of age, and bad health makes me unfit for hard field- 

 work. 



I am ashamed to send you such a shabby letter; but I wish not to miss the early 

 post of this day in order that I may correct the mistake or laziness of my publisher. 



I assure you that I am with great respect, my dear sir, very truly and gratefully 

 yours, 



A. SEDGWICK. 



Boston, May 14, 1855. 



* * * Your magnificent work on " Fossil Foot-Marks," I have this day received, 

 and have already distributed a number of the coi)ies. The honor you have done me 

 in dedicating to me so noble a work is one of the most gratifying circumstances of 

 my life, though I cannot feel worthy of it. Coming as it does from one who has so 

 long and so ably distinguished himself by his scientific labors, however, it is, whether 

 well founded or not, a high gratification. * * * 



Very respectfully, your friend, 



J. C. WAEREN. 



Cambridge, Mass., May 17, 1855. 



* * * I have read witb great interest your memoir in the Transactions of the 

 American Philosophical Society, and have been not a little surprised at the position 

 assumed by Agassiz in describing your specimens as well as in the lectures which he 

 has receutlj' given here. I cannot conceive that he has been led to his conclusions 

 by anything else than a foregone decision. The anatomical evidence seems to me 

 unmistakable. lam still more inclined to think that he has prejudged the matter 

 since, a few days ago, lie pronounced (not knowing their geological positron) the 

 specimens now before me as foot-prints of reptiles (as those of toads), and seemed 

 rather taken aback when I told him they were from coal strata. 



I feel that some apology is due for the liberty I have taken in addressing you with- 

 out personal acquaintance, but I trust you will be ready to pardon in the great in- 

 terest which attaches to the subject of early reptilian life, the evidence in relation to 

 which is so fast accumulating that I believe it will command the assent of the most 

 sceptical to a position as low as the coal and even to the Old Eed Sandstone. * * * 

 With great I'espect, truly yours, 



JEFFEIES WYMAN. 



Philadelphia, May 21, 1855. 



My Dear Sir: I am in receipt of your letter of the 17th, and beg to assure you 

 that it will give me great pleasure to afford you any information in my i)ower. 



I know of nothing new from the Eed Sandstone of Pottsville since Professor Eogers's 

 commimication to the American Association at Albany, except that Dr. Leidy last 

 summer found a small bivalve in the Tumbling Euu dam, which, however, he mis- 

 laid and did not come across again until about two weeks since, when he handed it 

 to me. 



I was preparing a paper on it when your letter was handed to me. It will appear 

 in the Proceedings of the Academy of Natural Sciences. 



I am very glad to find that Professor Eogers's specimens are in such good hands, for 

 I feel assured that you will do justice to all. I hope you will do me the favor to read 

 carefully what I have said in the memoir in connection with the geological position 

 of those "foot-marks." You will understand that although Professor Rogers said that 

 these '•'foot-prints" are of " an age essentially later than that attributed to them," 



