6 Anthracite formation of Wilkesbarre, &c. 
The vegetable impressions always accompany the super- 
incumbent schist and argillite; none have been found among 
the coal, nor any, or rather very few, in the carbon-im- 
pregnated argillite of the floor. I have, in this last, how- 
ever, met with the phytolithus verrucosus, figured by Martin 
in his Petrificata Derbiensia. 
The mass of the impressions are in the argillite immedi- 
ately in contact with the coal, although they are common in 
the coarse sandy schist* above it, and occasionally are found 
in the sand stone strata which alternate with the coal. There 
are above a dozen species of fern. A frequent impression, 
is that of a very broad-leaved, apparently, aquatic plant, pro- 
bably a sedge, with a transverse thread across the leaf at 
every three or four inches. This leaf is sometimes found 
of the breadth of six and even seven inches. Another very 
much resembles the leaf of the Indian corn, (zea mays,) or 
rather that which comes to us in boxes of tea. Occasionally, 
very perfect specimens of flowers of a stellated form occur, 
and rushes and a variety of singularly formed plants and 
jeaves, the originals of many of which are probably now lost. 
There are also numerous impressions resembling the bark 
of trees, or lichen attached to the bark, some of them 
forming tableaux four or five feet long, and a foot or more 
wide, so regularly and beautifully figured, that the colliers 
term them ‘jacket patterns.” These are very interesting, 
but the schist in which they are generally found, is so very 
friable, as to render it difficult to obtain any thing like large 
or perfect specimens; possibly they are aquatic alge. In 
general, the cryptogamic class prevails, to which the alge and 
filices belong—these last, in particular, are very numerous. 
Culmiferous plants also abound, but they are generally leaf- 
less, the impression of the stem alone being left. 
One or two of the beds here are worked by leaving mas- 
sive pillars eight or ten feet square at the base ; but with 
the exception of these, the beds, which are very numerous, 
are worked aw jour, that is, the superincumbent strata are 
first removed, when the coal is either blown off with gun- 
powder or taken off with wedges by drilling in a straight 
fine, at suitable distances, or from twelve to twenty-four 
inches apart, several deep holes about two inches in diame- 
* In this schist, the phy. cancellatus and tesscllatus, figured by Martin and 
Steinhauer occur. 
