When heated to nearly a red heat it gives a porous friable mass which is known as "burnt alum."
The eastern portion of the county is generally of a light friable soil; the southern portion rocky and barren, with but little bog except in the neighbourhood of Newtown-Hamilton.
In each province they had found the best springs, beds of clay, paint, soapstone, flinty rock, friable stone for sculpture and hard, tenacious stone for tools, and used ashes for salt.
The soil generally is a sandy loam or a strong but friable clay, and very fertile.
It forms a white friable mass which after ignition is insoluble in acids.
