298 Prof. Hitchcock on Ichnolithology, or Fossil Footmarks. 



" III the slabs of sandstone from Connecticut river in Montague 

 or Sunderland, lately brought here, I have obtained singular ap- 

 pearances, new to me, although I presume not to yourself. One of 

 them is distinctly marked with the tracks of a turkey (as I be- 

 lieve) in relief. There were two of the birds side by side, ma- 

 king strides of about two feet." 



*'I was anxious to see the die from which these impressions 

 were struck, and it has now arrived. The tracks, four in num- 

 ber, are perfect, and must have been made when the materials 

 were in a plastic state, and at what period I leave you to tell. I 

 am no geologist, but yet know that geologists derive much satis- 

 faction from contemplating these remains. I do not know but 

 they may be familiar to you ; but if you desire it, I will endeavor 

 to prevent their being converted to the use for which they were 

 brought here." 



My answer, bearing date March 15th, was as follows : 



" It would be a most interesting fact, if the suggestions you 

 make as to the impressions on sandstone, should prove true. For 

 I recollect but a single similar fact in geology, and that is the 

 tracks of a tortoise on the sandstone of Scotland, described in the 

 American Journal of Science a few years ago. I am not without 

 strong suspicion, however, that the case you mention may be a 

 very peculiar structure of certain spots in the sandstone, which I 

 have often seen in a red variety of that rock. The layers of rock 

 having this structure, sometimes present an appearance resem- 

 bling the foot of a bird. But I am satisfied that it is not the 

 result of organization, though I confess myself unable to say pre- 

 cisely from what principle it has resulted. But perhaps the case 

 you mention is not of this sort, and T should be quite glad to see 

 the specimens ; if you can prevent their being defaced for a month 

 or two, until I shall visit Greenfield, I shall be much obliged to 

 you." 



The peculiar structure of the sandstone in some places, re- 

 ferred to in the above letter, still remains to me inexplicable. A 

 specimen of it may be seen in the Massachusetts State Collec- 

 tion, No. 1793. This letter was written before Dr. Deane had 

 sent me a cast of the tracks. And hence my scepticism, since I 

 had repeatedly known a peculiarity of structure in rocks to be 

 mistaken for tracks. 



