322 Dr. J. W. Dawson ow Sjfo-e-cases in Coals. 



Itiiid. Gocp])eit mentioned and figured tliem in liis ' Treatise 

 on Coal' in 1848. Balfour described them in 1859 as ocem-- 

 rint>' in Scottish coals ; and Qiu;kett fi^t^ured them in his account 

 of the Torbane-llill mineral in the same year. In 185.5, the 

 latter microsco])ist showed me in London slices exliil>iting 

 round bodies of tliis kind, very similar to those now described 

 by lluxley ; but at that time I regarded them as concretionary, 

 though Prof. Quekett was disposed to consider them organic. 

 IMr. Carruthers has summed up most of these tacts in his ac- 

 count of his genus Fleininf/iiefi in the ^ Geological jMagazine ' 

 for October 18G5. The subject lias also attracted the attention 

 of microsco])ists in connexion with the Tasmanite or " white 

 coal" of Tasmania, which is composed in great part of the 

 spore-cases of ferns. 



I sup])Osc that the oldest spore-cases known are those de- 

 scribed by Hooker from the Jjudlow formation of the U|)per 

 Hihu-ian; but these, if really spore-cases, are different in 

 structure from those ordinarily found in the coal-foruuition, 

 more especially in the great thickness of their Avails, and I am 

 not aware that they have anywhere been found in considerable 

 quantities. 



The oldest bed of sj:)ore-cases known to me is that at Kettle 

 Point, Lake Huron. It is a bed of broAvn bituminous shale, 

 burning Avith much flame, and, under a lens, is seen to be 

 studded witli flattened disk-like bodies, scarcely more than a 

 lunulredth of an inch in diameter, which under the microscope 

 arc found to be spore-cases, slightly pa])illate externally, and 

 with a point of attachment on one side and a slit more or less 

 elongated and gaping on the other (figs. 1, 2,3). I have proposed 



Fig-. 1. Part of a slice of shale from Kettle Point, showinf>- two spore- 



casos and ri'maiiis of spores. iMa^n. 70 dianis. 

 rigs. 2 & 3. yporc-tasos from tlio same, as opaque objects. 70 diams. 



