128 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 7, 



constituting this seam were formed from drifted vegetable matter, 

 for we find layers of carbonaceous and argillaceous shale alternating 

 with three layers of coal whose united thickness amounts only to one 

 foot, which is precisely the arrangement likely to obtain from vege- 

 table matter drifted down with mud into an estuary. If then a seam 

 clearly formed from drifted materials assume this arrangement, it is 

 evident that thick beds of pure coal perfectly free from clay, or mud 

 mixed with vegetable matter, could never have been accumulated in 

 the same manner. 



I have marked all the beds in the section in which plants have been 

 found, but it is very probable that they occur in many other beds and 

 have been overlooked. The shales are the most prolific in plants, 

 especially those which form the roofs of the coal-seams. It is a sin- 

 gular fact, that not even the trace of a fossil plant, nor any organic 

 substance has been found in any of the red shales, although they have 

 been carefully examined for that purpose. Wherever erect trees occur, 

 ferns, Asterophyllites, Sphenophylla, and other delicate leaves, are 

 found in the greatest abundance, from which I infer that they fell 

 from growing trees and shrubs, having been covered up by successive 

 layers of fine mud deposited at frequent intervals over a low, marshy 

 district. In these localities single fronds of ferns are sometimes found 

 covering a slab of shale two feet square, as sharp and distinct in their 

 outline as if they had been gathered only yesterday from a recent fern 

 and spread out with the greatest possible care, not a single leaflet 

 being wanting or even doubled up. Some beds also seem to contain 

 one species of plant only, all others being excluded ; of this we have 

 a striking example in the argillaceous shale No. 60 ; in the top of 

 this bed, through a depth of three inches, we ^nA. Asterophyllites fo- 

 liosa piled up layer above layer from the base of the cliff to the crop 

 of the bed, a distance of 200 feet, clearly proving that these plants 

 grew on the spot. 



Plants are not very common in the sandstones ; those numbered 

 272, 282 and 310 are the only sandstones which contain any con- 

 siderable quantity : they consist of fragments of Sigillarise, Lepi- 

 dodendra, and Calamites confusedly mixed together, and evidently 

 drifted from a distance. 



The impressions of Fucoids without any carbonaceous matter are 

 found in several beds, as specified in the section ; in every instance 

 they occur on the undersides of hard arenaceous shales or sandstones 

 in contact with soft shales beneath. They appear to have been long 

 tubular stems, from one-tenth of an inch to one inch in diameter, and 

 are accompanied by detached ovate and globular bodies very much like 

 the capsules and vesicles of recent Algae. Fine ripple-marked sand- 

 stones are generally found very near to the Fucoids, and in two in- 

 stances impressions of rain-drops. 



The most interesting fossils in our section are the numerous groups 

 of erect trees situated at so many different levels, which I shall now 

 briefly notice, purposing to send to the Society more detailed de- 

 scriptions at a future time, having with that view taken an accurate 

 drawing of almost every indi^ddual tree. 



