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271 
tion of their constituents, yet I have no doubt some of them would af- 
ford a cement equal to any elsewhere made in its extensive range to the 
west. 
In the limestone at the Falls of Niagara, and of numerous other pla- 
ces, and in some of the water limes below that limestone, there is at 
the separation of the layers a singular columnar appearance, presenting 
itself at right angles to the layers, extending unequally as to length, 
bearing no small resemblance to the sutures of the scull. When exa- 
mined they show the impress of a parallel fibrous or striated appear- 
ance, which is almost invariably covered with minute scales of coaly 
matter. In vain I sought last year for the cause of this common ap- 
pearance. In examining the upper layers of the water lime in Herki- 
mer, the difficulty was solved: specimens were discovered with the 
strioe, and with carbonate of lime in minute fibres as to thickness, but 
not in length, clearly proving that the phenomena in question was caus- 
ed by the crystallization of a saline substance in fibrous crystals at the 
joints of the rock, analagous to those beautiful productions which all are 
familiar with, namely, the congelation or crystallization of water in 
loose and spongy soils. This explanation meets its confirmation in a 
specimen recently examined, which I brought last year from the Falls of 
Niagara, in which the striated appearance is finely exhibited, the speci- 
men being exceeding fresh and unaltered; on the top of the black or 
carbonaceous coating there are two small groups of fibrous sulphate of 
magnesia, which the force of crystallization has ejected since being in 
the cabinet, to the height of a quarter of an inch, and for want of a sup- 
port the ends coil over, as we find in the black part of the banks of 
our ditches and other low grounds. 
From finding last year the sulphate of magnesia with common salt as 
an efflorescence, below the upper falls at Rochester, and knowing that 
the fibrous form is the most common crystalline appearance of Epsom 
salts, I am disposed to believe that this mineral is the parent of the phe- 
omenon in question, the cause of which has been no small perplexity 
to others as well as to myself. 
The carbon which invests the strioe was a subsequent action, probably 
a deposition from the same water which dissolved the mineral, anala- 
gous facts being familiar to chemists. 
It is from the water limestone, and from the limestone which rests 
upon it, that the calcareous tufa, which is found in every valley or ra- 
vine that extends to the water limestone, owes its origin. These depo- 
