1870.] DAWSON — SPORE-CASES IN COAL. 373 



consist principally of cortical and ligneous tissues with layers of 

 finely comminuted vegetable matter. A layer of cannel, however, 

 from a bed near New Glasgow has numerous flattened amber- 

 colored discs, Avhich may be of this character. In those of Capo 

 Breton, the yellow spore case-like spots are much more abundant; 

 but these coals I have less extensively examined than those of the 

 mainland of Nova Scotia. Of American coals the richest in spore- 

 cases that I have seen, is a specimen from Ohio, which contains 

 many large spore-cases, and vast numbers of more minute globu- 

 lar bodies apparently macrospores. It quite equals in this respect 

 some of the English coals referred to by Huxley, (fig. 4). I have 

 also a specimen of Anthracite from Pennsylvania, 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 in- 

 dicate that their occurrence is accidental rather than essential to 

 coal accunmlation, 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 couls. 

 It is to be observed, however, that the conspicuous 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 exami- 

 nation of coals, to overrate their importance, and this I think has 

 been done by most microscopists, especially those who have con- 

 fined their attention to slices prepared by the lapidary. One 

 must also bear in mind the danger arising from mistaking con- 

 cretionary accumulations of bituminous matter for sporangia. In 

 sections of the bituminous 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 Psilophy ton 

 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. '=^ 



(1.) The mineral charcoal or " mother coal'' is obviously woody- 

 tissue and fibres of bark ; the structure of the varieties of which 



See also Acadian Geology, 2d edit., pp. I3S, 4()J, 493. 



