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in Mayfield. Beside this, in the same range, are numerous and beauti- 
ful varieties of the porphyritic, which, were they in more accessible si- 
tuations, would find their admirers and use. 
In the relative surface distribution of the rocks of Montgomery, it 
may be considered, that gneiss and black shale occupy rather more than 
two-thirds of the county, and in about equal proportions. The rubble- 
stone is the next in amount, then the calciferous sandrock, the Trenton 
limestone, and lastly, the birdseye. 
Muvial. — From the greatness of the action of waters in remote pe- 
riods, the alluvial is of great magnitude. Extensive ranges of sand hills 
skirt the region of primary rock in many parts, and the course of what 
appears to have been the outlet of elevated bodies of water. Along the 
borders of the Mohawk, and in the banks of innumerable other streams, 
clay, gravel and sand, often attain the height of an hundred or more feet. 
So great has been the cause of alluvial product, and so numerous are the 
localities of the product, as well in the other counties examined as in 
Montgomery, that to enumerate the respective localities of clay for pot- 
tery and bricks, gravel for road making, &c. &c. would cause this report 
to exceed all reasonable bounds, and therefore with more propriety will 
form material for the scientific detail of the final report of this district. 
It is highly probable that the clays are all more or less of the fusible 
kind, from the abundance of carbonate of lime contained in those rocks 
which have been most exposed to the destructive agent. The infusible 
clays being formed of silex and alumine, the addition of lime or oxide of 
iron gives fusibility, the degree varying within certain limits with the 
quantity added of those materials. 
The sand which borders the primary region is the purest, as might be 
supposed from the nature of the rocks which has given rise to it, and 
is suitable for glass making, cement, &c. whilst that of the Mohawk and 
its tributaries is usually much sullied by the influence of its dark colour- 
ed associates. 
Of the Ores of Mmigamery county. — In Flat-creek, south of the Mo- 
hawk, about one mile from Spraker's basin, consequently within the li- 
mit of the uplift of the Noses, lead ore for some time has been the sub- 
ject of research. It is sought for in the black shale which at the mines 
forms the vertical sides and the bottom of the creek. From the rock be- 
ing uncovered, an admirable opportunity is presented for the examina- 
tion of the innumerable small veins or rather strings of lamellar carbonate 
