’ 
S. W. Ford—Primordial Fossils of New York 35 
Mr. Bakewell in this Journal (see January, 1857, pp. 87-93) 
was not far from correct; namely, about three feet a year, 
which would make the time required not over ten thousand or 
twelve thousand years. These rates of recession have been re- 
cently obtained by Dr. Pohlman by comparing the position of 
the horseshoe fall fixed by Professor Hall’s survey of 1841 and 
the position as determined by the United States Survey in 1875. 
Dr. Pohlman’s paper will soon be published in the Proceedings 
of the American Association. Mr. James T. Gardiner, of the 
present New York Survey, informs Professor A. Winchell (see 
World Life, p. 871) that this rate cannot be far from correct. . 
he rate of recession for Niagara falls corresponds with _ 
inferences drawn from the amount of post-glacial erosion which 
has taken place in the numerous small streams of Northern 
Ohio emptying into Lake Erie. For example, there is at Elyria, 
Ohio , a waterfall in Black River, a small stream about thirty 
miles in length. The gorge below the falls, which represents 
the work done by that stream since the Glacial period, is only 
about sixteen hundred feet in length; and this is about the 
length of numerous other gorges in Northern Ohio where small 
streams break over the Waverley sandstone into Lake Hrie ; and 
so everywhere the contrast between the amount of erosion ac- 
complished by streams in corresponding strata in post-glacial 
ime and that done in pre-glacial time, such as indicated in the 
statement just made concerning the Ohio, is perfectly aston- 
Oberlin, Ohio, May 2. 
Art. VI.—WNote on the Discovery of Primordial Fossils in the 
Town of Stuyvesant, Columbia County, N. Y.; by S. W. Forp. 
ON page 406 of Mather’s Report on the Geology of the First 
District of the State of New York, published in 1843, atten- 
tion is called to certain brecciated and conglomerate limestones 
Occurring in the extreme northwestern: portion of Columbia 
County; and on plate 23 (fig. 8) of the same work, a section is 
given to illustrate their stratigraphical relations. The rocks 
are treated of by the author in the chapter devoted to the 
consideration of the Birdseye and Black River Limestones ; 
and although no fossils are cited from them in proof, the series 
1s regarded as not improbably an inverted one, the older masses _ 
occupying the summit of the section. I have recently Vt 
i her’s 
with some care the rocks referred to, and find 
section to be substantially correct, except that I do not find pie 
go tee courses in his lower division (a). = 
_ the. strata in question make a conspicuous feature in the — 
