DRIFT, ETC. 33 



jock at the time when it was thus scored. Notwithstanding this 

 jact seems so well determined, and moreover that a suspension for 



time of a deposition of the peculiar materials of this rock, still, 

 he layers which succeed the worn and polished surface are those 

 if the Trenton limestone. In Plattsburgh we find surfaces with 

 |ie ancient and modern scorings within ten feet of each other, and 

 ly comparison on the spot no one can observe any difference in 

 le character of the markings themselves ; though the former, as 

 as been stated, run east and west, while the latter run north and 

 )uth. I had observed similar phenomena at Essex, several years 

 lefore this observation at Plattsburgh, and so stated the fact in 

 pe of our annual geological reports ; but subsequently, fearing I 



id committed an error in my statement, made what I intended a 



)rrection in a subsequent report. This, however, seems to 

 |ive been unnecessary. But as the facts seemed to me so extra- 

 I'dinary, and had not at the time been noticed by any geological 

 jriter, I deemed that course right when there appeared some doubt 

 j to the correctness of the observation. Mr. James Hall has pub- 

 |;hed in the reports, and elsewhere, an essay on mud furrows, 

 'aese present phenomena in part similar to the scorings of rocks 

 if diluvial action ; still, in no instance which he has given, nor in 

 iiy which we have observed, is the rock beneath polished. In 

 ijis case there is a hard, sandy rock, the inferior surface of which 

 ij marked in relief by parallel ridges ; the surface upon which 

 lis reposes is a fine and soft argillaceous mass, and was probably in 

 t|2 state of mud when the marked stratum was deposited ; but it 

 iinot polished, nor does it appear that the phenomena in the two 

 cses are produced by causes of the same nature. All these facts 

 a^ so many incidents in the history of the earth. We may truly 

 s/ that wherever we go, or on whatsoever side we turn our eyes, 

 tere we find interesting changes ; these changes reveal many of 

 tt; former conditions of the earth. The collection and recital of all 

 tl'se phenomena will be hereafter formed into a complete and per- 

 f<|t history ; and the rapid accumulation of facts within the last 

 qirter century, indicates that the time is not far distant when this 

 htory will be written. 



ilbany, June 1, 1845. 



OL. II. — NO. I. E 



