326 
[Assembly 
About .two miles west of Newark, on lots 84 and 85, are two hills, 
one on either side of the Erie canal, from which gypsum is quarried, and 
principally on lot 85, owned by Winslow Heth. The gypsum at this 
locality is mostly lamellar, transparent, and is of that variety which re- 
ceives the local name of isinglass plaster. It is sometimes reddish,, 
and rarely crystallized; it is mixed with or disseminated in a calcare 
ous or argillaceous marl. Several varieties of gypseous marl occur here,, 
slaty, green, red, and variegated. The reddish Selenite occurs at the low- 
est point in this hill, and was taken from the reddish or variegated marl. 
This quarry was opened seven years since, and from 2,000 to 3,000 
tons have been extracted. It occurs in large, rounded, irregular masses. 
Sells for $2.50 to $3 per ton. Blackmar's quarry is immediately op- 
posite, and on the south side of the canal. The plaster is of the same 
quality as at Heth's quarry. 
A considerable proportion of the gypsum at Heth's quarry is trans- 
parent, and consists of leaves or laminae. This variety also occurs at 
the plaster beds in the neipjhboring counties, associated and mixed with 
the granular, compact, or slaty gypsum, and is generally known by 
the local name of Isinglass Plaster. A strange prejudice prevails with 
regard to this variety, which in some places also extends to the fibrous 
gypsum. It is consideredan impurity^ and to be injurious as a ma- 
nure, and consequently those masses which contain it are excluded 
and thrown aside. This opinion is entirely erroneous, for the transpa- 
rent and fibrous varieties are a purer article than the opake, granular or 
compact forms of gypsum, and their transparency is occasioned merely 
by their crystalline structure. Nearly one half of the Nova-Scotia plas- 
ter consists of the transparent, lamellar, and fibrous varieties, which 
have been excluded at these quarries as an impure article. 
We take this occasion of presenting our acknowledgments to James 
R. Reese and Wm. S. Stowe, Esqrs. of Clyde, to Col. Elias Cook of 
Sodus Point, to Dr. Williams of Newark, and to Levi Hendrick, 
Esq. of Wolcott. To the above gentlemen we are indebted for personal 
attentions, and for much valuable information and assistance rendered to 
us during the examination of Wayne county. 
