AS COMPARED WITH THAT OF THE PRESENT DAY. 



427 



Ulodendron. — This very remarkable genus scarcely differs from Lepi- 

 dodendron in internal structure : its external aspect widely departs from 

 that of any plant, recent or fossil, with which I am 

 acquainted. I have seen in collections, speci- 

 mens which have been fossilized, apparently erect, 

 or at any rate, under very different circumstances 

 from those preserved in the shales over the coal. 

 They present the appearance of a large un- 

 branched zigzag trunk, with two rows (opposite 

 one another) of alternating cup-shaped deep 

 depressions, one at every projecting angle of the 

 trunk. Some idea of the appearance of these 

 specimens might be gathered from the accom- 

 panying wood-cut. Mr. Dawes showed me a 

 specimen preserved in sandstone, with a large 

 organ which he considers to be a cone inserted 

 into one of the cup-shaped depressions. I could 

 not, however, form any conclusion concerning 

 the real nature of this highly interesting ex- 

 ample. 



Knorria. — A genus of which very little is 

 known. Dr. Lindley* pronounces the K. taxina 

 to be certainly coniferous, comparing it with a 

 leafless branch of the common Yew; to me it 

 appears to have quite as much resemblance to 

 the stem of a Lycopodium, especially of L. phlegmaria.\ 



The K. Sellonii again, is remarkably similar to what I have con- 

 sidered as much compressed specimens of Stigmaria ficoides, which are 

 very much compressed but not entirely flattened, and in which the 

 cellular tissue has collapsed, leaving the vascular bundles which meet 

 the circumference at the areola? projecting beyond the surface : — this, 

 however, is only a suggestion. 



Calamiteos. 



I have in vain sought for any traces of structure in carefully prepared 

 species of this genus ; or for evidence of their being Equisetacece in the 

 presence of those siliceous stomata with which that order abounds, and 

 which would surely have been preserved in the fossil state. 



Very fine specimens of this genus were pointed out to me on a cut- 

 ting of the Manchester and Bolton Railway by Mr. Binney : they were 



* Lindley and Hutton, Fossil Flora, sub. K. taxina, tab. 95. 



f Compare the figure of the stem of this plant given in Brongniart's Hist. Veg. Foss., 

 tab. 7, fig. 11, with Lindley and Hutton's figure v. 2, t. 95. 



