£92 
Mr. Weaver on the 
Some other impressions agree with Parkinson, voh L PI. 5. fig, 8* 
(which is on the coal shale of Haigh in Lancashire). 
Delicate impressions, which resemble very nearly the hyme- 
nophyllum tunbridgense, also occur, but they are comparatively 
rare.. 
The shale displays a great variety of impressions, particularly of 
such as bear resemblance to ferns, reeds, and grasses, most of the 
prototypes of which are probably unknown. Some of these present 
a surface, more than two feet in length, and two, three, or four 
inches wide. The most numerous impressions of the fern tribe 
appear referable to the blechnum spicant. Impressions are occa- 
sionally found in the clay ironstone also. 
The colliers informed me that very rarely small shells were dis- 
covered in the roof shale of the Coaibrook seam ; and I myself 
found a few of these reputed shells, displaying a rich glossy smooth 
surface, and inserted in the shale without order, frequently crossing 
the laminated structure of the stone. They were, however, very 
indistinct, and it is doubtful whether they may not be the casts of 
the seed vessel of a plant, the nucleus sometimes consisting of iron 
pyrites, and sometimes of shale, while the glossy surface betrays, 
nothing of a calcareous nature. But, on the other hand, the roof 
shale of the twenty inch seam, below that of Coaibrook, contains 
very decided impressions of shells ; those resembling winged ano- 
mias being particularly distinct, with the outlines of the shell well dis- 
played. The shells appear to have undergone gradual compression 
and solution, for the surface represented in the shale is perfectly fiat, 
and in the direction of the lamina of the stone ; but not a trace of 
the matter of the shell remains. 
The late Mr. Tighe notices the occurrence of shells also in the 
Castlecomer coal shale, which likewise exhibits impressions of ferns. 
