Dr. J. W. Dawson on Spore-cases in Coals. 



325 



iilil"i:ii' Wi:",,t^N pii ii;:'iiifi!t'.'';i:fnin:i[[ir' .| viii >i.ik'9HI).,M 



I'art of a slice of ( Jliio coal, show- 

 ing at one side a pai-t of a large 

 spore-case and numerous spores. 

 Magn. 70 dianis. 



cannel, however, from a bed near New Glasgow, has nume- 

 rous flattened amber-coloured 

 disks, which may be of this 

 character. In those of Cape Bre- 

 ton, the yellow spore-case-like 

 spots are much more abundant ; 

 but these coals I have less ex- 

 tensively examined than those 

 of the mainland of Nova Scotia. 

 Of American coals, tlie richest 

 in spore-cases that I have seen 

 is a specimen from Ohio, which 

 contains many large spore-cases 

 and vast numbers of more mi- 

 nute globular bodies, apparently 

 macrospores. It quite equals in 

 this respect some of the Eng- 

 lish coals referred to by Huxley 

 (fig. 4). I have also a s])ecimen of anthracite, from Penn- 

 sylvania, full of spore-cases, some of them retaining their 

 round form, and filled with granular matter, which may 

 represent the spores. 



It is not improbable that sporangites, or bodies resembling 

 them, may be found in most coals ; but the facts above stated 

 indicate that their occurrence is accidental rather than essential 

 to coal-accumulation, and that they are more likely to have 

 been abundant in shales and cannel coals deposited in ponds 

 or in shallow waters in the vicinity of Lycopodiaceous forests 

 than in the swampy or peaty deposits which constitute the 

 ordinary coals. It is to be observed, however, that the con- 

 spicuous appearance which these bodies, and also the strips and 

 fragments of epidermal tissue which resemble them in texture, 

 present in slices of coal, may incline an observer not having 

 large experience in the examination of coals to overrate their 

 importance ; and this, I think, has been done by most micro- 

 scopists, especially those who have confined their attention to 

 slices prepared by the lajiidary. One must also bear in mind 

 the danger arising from mistaking concretionary accumulations 

 of bituminous matter for sporangia. In sections of the bitumi- 

 nous shales accompanying the Devonian coal above mentioned 

 there are many rounded yellow spots, which, on examination, 

 prove to be the spaces in the epidermis of FsUophyton through 

 which the vessels passing to the leaves were emitted. To 

 these considerations I would add the following, condensed from 

 my paper above referred to, in which the whole question of 

 the origin of coal is fully discussed* : — 



* See also 'Acadian Geology,' 2ud edit. pp. 138, 461, 493. 



