415 



about Newcastle and Durham call it plate. The stratum of this is 

 about a yard thick, lying 120 feet deep, and SO feet above the 

 Canel-coal. One specimen he describes as a black slaty coal, 

 marked in a quincunx manner, &c. much like what might have 

 proceeded from the bark of common fir. Another he describes 

 as having the appearance of long striated leaves, having the ap- 

 pearance of joints, &c. upon a dark grey slaty stone. The stra- 

 tum of this, he says, lay at the depth of 25 fathoms, in Bransty- 

 cliff, by the Duke of Somerset's salt-pans, near Whitehaven. The 

 stratum, he says, was about a foot and a half thick ; and upon the 

 breaking of the stone, leaves of plants appeared very thick in all parts 

 of it, where the grain of the stone was thus fine and dense. But 

 where it happened to be more gritty, coarse, and lax, there was not 

 one leaf to be met with*. Specimens of schisti thus bearing impres- 

 sions of vegetables are displayed Plate I. Fig. 6. and 7. ; Plate IV. 

 Fig. 6. and 7. ; and Plate V. Fig. 1, 2, 3, 6, 7, 8, 9. 



The impressions of leaves are much more rarely discovered in the 

 sand-stone strata, and are traced with much more difficulty ; owing 

 in part to the uncertain direction, in which these stones often split ; 

 and, in part % to the leaves being twisted, and to their laying in a 

 confused and irregular direction : hence the leaf is generally divided 

 with the stone, and its edge, or section, only exposed. Sometimes, 

 however, a very fair impression of a leaf may be seen, on sand- 

 stone ; but it will be found, in general, to differ very much in some 

 respects from the impressions on the argillaceous schists. Plate V. 

 Fig. 4. and Plate III. Fig. 3, 4, and 5. represent the impression of 

 vegetables on different kinds of sand-stone. 



The occurrence of vegetable remains in lime-stone strata is un- 

 doubtedly much more rare than in the argillaceous, or schisti. 

 Schultzen suspects some error in those accounts which state their 



* Catalogue of English Fossils in the Collection of J. Woodward, M.D. Part II. p. 16. 



