Geological Reports on the State of New York. 43 



Prejvdice against pure Gypsum. — " A considerable proportion of the 

 gypsum at Heth's quarry is transparent, and consists of leaves or laminae. 

 This variety also occurs at the plaster beds in the neighboring 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 considered an impurity, and to be 

 injurious as a manure, and consequently those masses which contain it 

 are excluded and thrown aside. This opinion is entirely erroneous, for 

 the transparent and fibrous varieties are a purer article than the opake, 

 granular or compact forms of gypsum, and their transparency is occa- 

 sioned merely by their crystalline structure. Nearly one half of the 

 Nova Scotia plaster consists of the transparent, lamellar, and fibrous va- 

 rieties, which have been excluded at these quarries as an impure article." 



Shore of Lake Ontario and Height of the Water. — " The action of 

 the waves, together with the ice, have raised beaches, which in many 

 places protect the land from inundation during high winds. In the east- 

 ern part of the county, the banks are abrupt, consisting of gravel, sand, 

 and clay. These banks are gradually worn away by the waves, and the 

 materials carried to points where the banks are low. By this wearing 

 action, the lake encroaches upon the land in some places, while the 

 land is gaining upon the lake in others. In the course of a year, sev- 

 eral feet of these banks are abraded by the waves. During some years, 

 the lake is higher than in others, so that the wearing action is not uni- 

 form." 



" For the last two years the laJce has been higher than for many years 

 before ; this is evidenced by the waves undermining the banks which had 

 become overgrown with trees and shrubs. There is a tradition of a pe- 

 riodical rise of the lake, but it is not verified by observation. Although 

 this rising of the lake is not periodical, it does occur at intervals, and at 

 such times the beaches and sand bars are removed, to be deposited in 

 other places, and to fill up the mouths of streams. It therefore becomes 

 a matter of importance to protect the shores from such effects, and from 

 the loss of land thus sustained. To do this, trees and shrubs should be 

 permitted to grow on the banks, and shrubs with strong roots might be 

 planted to effect the same object." 



The waters of all the great lakes have been unusually high, 

 for two or three years past — in some places six to seven feet, and 

 extensive inundations of valuable lands, and of houses, and other 

 buildings have been the consequence. 



At Buffalo on Lake Erie, when in September last, we had oc- 

 casion there to observe the fact, the waters had begun to subside, 

 and this is understood to be generally the case. The best reason 



