[ 548 ] 
“ land, and Friezland, are of this mineral wood, 
“ chiefly becaufe moft of them are found without 
“ knots or roots/’ 
Dr. Morton, in his natural hiftory of Northamp- 
tonshire *, mentions two or three varieties of this 
metallophyton ; one of which he defcribes, as of 
« a dark colour, and having a grain ; for in one di- 
“ region (which is ufually according to the length 
“ of the pieces), it cleaves or parts pretty readily 
“ into plates and fplinters, the other way it fnaps 
<c into Shorter pieces, and will not cleave at all. 
“ There is another fort, which does not fo readily 
part into flakes. None of theSe are found in any 
« large maSTes. They are all, more or lefs, of a 
<( glofly black, and have a denfity or fmoothnefs within 
«« like that of bitumen, or jet. In that alio, they 
«« refemble the true bitumen, or piflfaphalton. They 
<c are not fo firm and hard as the common coal, and 
* c are much brittler than canal or jet. They like— 
« wife all of them agree pretty nearly in the fame 
« properties. In water they fink. They are all in- 
« flammable, but confume Slowly in the fire, and 
emit a fomewhat unpleaSant fume, not unlike that 
« of bitumen, only fainter.” 
Of the fame kind is the inflammable Slate, or coal, 
of DorfetShire, found in the cliffs at the north-weSl 
corner of the ifle of Portland, near the caflle, of 
which I have received the following account from a 
gentleman of that county. The upper Stratum is the 
natural black earth 1 4 f ee * deep ; the next is a gieyifh, 
Soft, paving Slone, 6 inches thick j then follows the vein 
* Page 32i > 
of 
