Note by the author.— As/may be seen by the date of the accompanying letter to Captain 



without any apparent probability of its publication, that I had long since abandoned all expecta- 

 tion of ever seeing it published. I had, however, long back, published brief notices of the new 

 forms collected by the expedition, in the Proceedings of the Academy of Sciences at Philadelphia, 



Alter the elapse of so many years without any prospect of the publication of Captain Simp- 

 son s report, bring aware how very <lt sii aide it is that figures and descriptions of all named spec ies 

 should be placed within the reach of palaeontologists, I availed myself of the opportunity to pre- 



should not have done, had I known that Captain Simpson's report would be published 'even at this 

 late date. The appearance of some of the same species, however, in two different reports is really 

 not a superfluity, as the tigires and descriptions appear in connection with reports of distinct 



changes of nomenclature, &c, to bring it up to our presold knowledge of the paleontology and 

 geology of the far West. In doing this. I have tried, as far as possible, by inserting the dates of 



ot this report, fifteen \ears back, to do full justice to the subsequent tabors of others, as well as to 



n Institution, November 8, 1875 



