ERIE DIVISION. 321 
tack creek, between the townships of Cairo and Athens, and in the beds of the streams in 
various parts of Greenville, and in the west parts of New-Baltimore and Coxsackie. 
The finest exposure of these strata was observed in Coeymans, Albany county, along the 
banks of the Hawnakrans kill and its branches, as far up in the series as the flag-stone -stra¬ 
tum. The strata are not all exposed in the bed and banks of the stream, but they may be' 
easily traced out on the table lands north of it, on the road to Clarksville, on which they are 
exposed in successive broad terraces with steep escarpments, offering every facility for mi¬ 
nutely examining their fossil contents.* The south part of Bern, and nearly all the town¬ 
ships of Westerlo and Rensselaerville are occupied by the strata of the Erie division. The 
Marcellus shales are largely developed, overlying the limestone of the Helderberg division in 
Coeymans, Bern and Knoxville, but fossils are rare. In some places it is so black as to 
have led to search for coal. The Hamilton, Ithaca and Chemung groups, occupy most of 
Rensselaerville and Westerlo, and a part of Bern. 
More than one half of Schoharie county is occupied by the rocks of the Erie division, and. 
they are beautifully exposed to observation in very many places. The roads from Middle- 
burgh bridge by Byrnville to Summit; from Hyndsyille over the mountain by Richmondville, 
to Summit; from Summit to Jefferson Academy; from this last place to North-Blenheim, 
and thence to Gilboa and Strikersville, offer fine opportunities for examining the strata, but 
they are better exposed in the neighboring ravines, and at the numerous falls on the small 
streams. Fossils were seen in many places on these routes by the road sides in the rocks in 
place, but they are rarely abundant as they are in the same rocks farther west. 
The valley of Schoharie creek between Middleburgh bridge and Gilboa, also offers fine 
opportunities for examining these strata; and the valleys of the small streams that flow into 
the Schoharie kill offer still better opportunities. 
Above the Helderberg limestone series, south of Hyndsville, in Schoharie county, a shale 
or slaty crumbling grit was observed, which is a part of the Marcellus shales. 
Above this, a series of rocks occurs, composed generally of fissile sandstones, and contains 
many strata abounding in testacea of various species ; also fucoids and terrene plants. This 
is the Hamilton group of Prof. Vanuxem. 
Shells were seen in many places in the grits and gritty shales, betweenSummit and Jeffer¬ 
son Academy, especially on the high grounds and on the tops of the hills. They are particu¬ 
larly abundant about one mile north of Jefferson Academy. There are several strata abound¬ 
ing in marine testacea, between Summit and Richmondville, and the same strata are crossed 
on the road thence over the mountain to Hyndsville. Other strata abound in plants. The 
shell strata may also be seen on the road from Summit to Byrnville, in the town of Fulton. 
■* This is the northeastern extremity of that formation; and each stratum, at its outcrop to the north and east, occupies a terrace 
of greater or less breadth. In many localities, the greatest facilities are thus presented to the collector of fossils, to procure 
numerous fine specimens of these medals of a former epoch, and also to the quarryman to quarry extensively, with little or no 
expense in uncovering the particular strata of rock that may be desired. 
Geol. 1st Hist. 41 
