236 
[Assembly 
I of a mile west of Greenville, Greene county, on land of Francis 
Hikok, Esq. It is well located, within a few miles of the Hudson 
river, in a highly cultivated country, and in the bracing air of the Cats- 
kill mountains, 
A chalybeate spring was observed three miles from Oak-Hill, on the 
road to Freehold, north of the turnpike, on the farm of Walter Bar- 
low. The owner did not know of it until informed. 
A mineral spring is said to occur near North-Blenheim post office, 
I did not see it. 
A sulphur spring was visited in RensselaerviUe, Albany county, in 
the valley of Fox creek, three miles from Preston Hollow. This is a 
moderately strong hepatic water, and flows at the rate of a gallon in 
four or five minutes. It is much used by the people in the vicinity. 
It is said to be somewhat diuretic in its efiects. The spring is on the 
farm of Mr. Weeden. 
IIL HELDERBERG LIMESTONE GROUP, 
This group embraces a series of limestones, varied in mineralogical 
character, in chemical composition, and which abounds in fossil re- 
mains. It contains subordinate beds of shales, slates and silicious 
grits. It skirts the group of rocks last described, in a parallel zone, 
and underlies them, it is supposed, through their whole extent. 
This formation extends in the district under examination, from Sha- 
ron Springs, in Schoharie county, by Schoharie, to the northeast part of 
the Helderberg mountains ; thence southeast, to near New-Baltimore ; 
thence southwardly, by Catskill and Saugerties, to Rondout; thence up 
the valley of the Rondout, by Rochester, Wawarsing and Ellenville ; 
thence on through the Mamakatting valley, by Cuddebackville, to Car- 
penter's Point, on the Delaware. At the latter place, it passes out of 
the State of New-York into New-Jersey, and crosses the Delaware 
into Pennsylvania, at the Walpack bend of the Delaware, according to 
Professor Rogers.* 
This formation varies much in its subordinate beds in different loca= 
lities, particular beds being either entirely wanting, or replaced by 
others ; but its fossil contents are nearly uniform. Mr. John Gebhard, 
* Vide Professor Rogers' 2d Annual Report on the Geological Survey of Pennsylva- 
nia, p. 56. 
