No. 200.J 
259 
Trenton limestone only. The third and last is at Fort-Plain, and one, 
too, of great interest. 
Why we have been so particular in giving these details, is from the 
circumstance that all the quarries along the Mohawk, either for lime or 
building stone, owe their origin to these uplifts, and since the great and 
extensive public works have commenced, giving impetus to private im- 
provement of all kinds, the importance and great value of these quar- 
ries is fully appreciated by every one connected with them. Moreover, 
when the present quarries are exhausted, knowing the uplifts, the or- 
der of arrangement of the rocks which compose them, the direction of 
the dip or inclination of the layers, all which knowledge is readily at- 
tained by examination, the discovery of others will be attended with 
no difficulty. 
The birdseye is the principal rock which is quarried for the public 
works, though the lower layers of the Trenton, especially near Am- 
sterdam, are likewise used; there they occur much thicker than observ- 
ed in any other part of the third district, excepting the upper layers of 
the same rock in Oneida, called in the report of Mr. Conrad, the gray 
crinoidal limestone, that part of the Trenton limestone not being found 
either in Montgomery or Herkimer county. The principal quarries and 
localities of the birdseye limestone are at Helmicks, Canadas and 
Klocks, on and near Crumb creek. Palatine church, Ephratah, Fort- 
Plain, Flat creek, Tribe's-Hill, Amsterdam, on both sides of the river, 
near Evaskill, Marcellus quarry, between the kill and Chucteronde 
creek, and at Peter Fonda's, in Claus patent, town of Mayfield. 
At the quarry of Palatine church, the best preserved fucoides demis- 
sus or stylastrites of Prof. Eaton are to be found. This is the fossil 
which characterises the birdseye. Whilst the fucoides in all the other 
rocks are disposed parallel to the layers, these are vertical, as though in 
the position in which they grew, a circumstance not confined to one 
place or locality, but almost invariably common to them all. 
Calciferous Sandrock. — Few rocks of the third district present so ma- 
ny features of general interest as this rock. Like most sedementary 
ones, it is in well defined layers, easily quarried, of the required thick- 
ness for ordinary masonry, and undergoes little change by exposure to 
the air. This rock is very variable in character and composition, as 
well in different parts of its mass as in different localities. In general, 
as its name signifies, it is composed of carbonate of lime and sand, in 
no fixed proportion, varying so greatly as often to be wanting in one 
