14 



A thin stratum of red ferruginous stone, containing a large propor- 

 tion of oxide of iron, is found in this region, running horizontally 

 below, and sometimes in the beds of clay before described, and ge- 

 nerally separated by only a few feet from the underlying masses of 

 shells. This stratum, which is very generally present, varies in 

 thickness from an inch to a foot. Its texture is sometimes cellular, 

 sometimes compact and fibrous, like that of certain varieties of he- 

 matite. In the more eastern portions of the Miocene district, the 

 peculiar structure of which will be hereafter described, much ore of 

 this description lies loosely scattered on the surface ; while in the 

 more elevated parts of the country, its invariable position is such as 

 above described. The character of the ore in many localities is such 

 as to promise great facility in reducing it to the metallic state, toge- 

 ther with a large per centage of resulting metal. A specimen ob- 

 tained from above the marl on the cliff at Mount Pleasant, Surry 

 county, yielded by analysis in the 100 grs. 



per oxide of iron, 



72.40 



alumina, 



3.90 



silica, 



7.71 



water, 



14.35 



98.36 

 Loss, 1.64 



100.00 



With a sufficient supply of ore like this, accompanied with the ad- 

 vantage of a shell limestone sometimes beautifully crystalline, in its 

 immediate vicinity, the manufacture of iron would promise a high 

 degree of productiveness ; and it is by no means improbable that in 

 some parts of this region the supply of the ore may be found suffi- 

 cient to make such an enterprise not only safe but profitable. The 

 subject is at all events worthy of some attention. Indeed it appears 

 not a little surprising that this rich mineral seems hitherto to have 

 escaped observation, or at least to have been regarded as undeserv- 

 ing of an especial notice. 



In some places, as for example, in Essex county, chiefly upon the 

 ridge land, beds of a ferruginous sandstone are found of sufficient 

 extent to be used as a building material. This rock is not to be 

 confounded with the sandstones which occur some distance to the 

 west of this, on the borders of the primary region, but it is to be 



