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I Assembly 
True it is, however, that carbon is abundantly diffused through this 
argillite, and that thin seams of anthracite can be exhibited in many- 
places. 
Anthracite is also disseminated in the graywacke in masses from the 
size of a pin head to that of a pea, so as to give the rock quite a hand- 
some appearance. This is strikingly the case at Walden, on the north- 
west bank of the Walkill. 
The argillite, and its associated graywacke and graywacke sjate, no 
where rise into lofty mountains. When this circumstance is recollected 
and taken in connection wdth what has been stated of the extent of this 
rock forming the great valley of the Walkill, it will be perceived at 
once how greatly it modifies the surface of the country. There is ano- 
ther remark should be made in this place, in relation to the rock of 
which we have been speaking. The argillite portion of the county of 
Orange embraces an unusual number and extent of swamps, or as they 
are called, bog meadows. They are all formed by bars of argillite rock 
across their outlets; this is true from the great drowned lands down to 
those which cover only an acre or two of surface. The useful purposes 
to which this rock is applied, are not numerous. The most important 
one at present, is in the construction of fire places and the lining of 
furnaces. When placed with the edges of the laminse to the fire, it 
remains for a long time iminjured. Some varieties in this county, which 
are not silicious, are excelled by no stone, for this purpose. The quar- 
ries of Mr. Bulmer, at Sugar Loaf, furnish excellent stone in abun- 
dance; they are sold at from $2 to $5 per load, at the quarry. It is also 
quarried to some extent on the western shore of Big Long pond, as a 
fire stone. Roof slate might be obtained abundantly, very similar to 
the Welch slate, but none is wrought for this purpose. 
The argillite is also employed to some extent in the construction and 
repair of roads; it is, however, but a poor material for this purpose. 
The surface edges of the rock are generally employed, and these of the 
variety containins; the largest proportion of clay. The wheels soon re- 
duce it to powder so fine that the wind drifts it when dry, and the wa- 
ter washes it away when wet. 
Beds of silicious slate and Lydian stone are embraced in this argillite. 
I have also seen graphic slate, but it is not abundant. Li some places, 
the graywacke associated with the argillite forms a tolerably good build- 
ing stone. It quarries very well, and works well under the hammer, 
but it requires great experience in selecting the layers, to avoid those 
