Geological Communications. 125 



Extract from Judge Thompson's letter. 



During my last visit at Troy, you strongly pressed me to commii- 

 nicate the result of some observations, through the medium of the 

 American Journal of Science. My reason for hesitating on this sub- 

 ject is, that all my observations may have been anticipated. But at 

 your request I will state, that for twenty years I have been forcibly 

 struck with the following phenomena. Wherever the earth has been 

 removed, leaving the horizontal graywacke bare, scratches and deep 

 grooves are observed running a few degrees north of a due east 

 course. I have observed this fact in more than fifty places, where 

 the earth has been removed in the construction of turnpikes, com- 

 mon roads, mill works, Sic. But they scarcely ever appear on 

 rocks which have been exposed to air, rain, Stc. When these 

 scratches first attracted my attention, I was almost a stranger to the 

 writings of geologists; but I could not resist the inference, that 

 they were made by heavy rocks or boulders, driven over the sur- 

 face of the upper layers of graywacke by the waters of the del- 

 uge. I was even inclined to infer, that the scratches indicated 

 the direction of the oceanic waters. I did not venture on the opin- 

 ion, that the waters moved in precisely the same direction in all 

 places; but that here, in Sullivan county, such was their direction. 

 I supposed that the general direction was every where the same ; 

 but that the particular configuration of mountains, valleys, &£c. might 

 give local variations to the course of the mighty movements of wa- 

 ters many miles in depth. 



After ten or twelve years, I became acquainted with several geo- 

 logical works which gave the waters of the deluge a direction from 

 north west to south east. I have only to say, that if these scratches 

 indicate this direction, such could not have been their course here. 



If these facts, which I should be pleased to point out to Prof. Sil- 

 liman, or any other geologist travelling this way, (to whom I ofier my 

 house for a home,) should be thought worthy of any consideration, 

 I may venture to present additional results of my observations, made 

 in this place and its vicinity, during the last thirty years. 



Respectfully your friend, William A. Thompson, 



Amos Eaton, Esq. 



