Geological Society. 151 



Seen from another point of view, however, these plates become 

 immediately valuable j for though the objects engraved were too 

 indistinct perhaps to enable us to determine the genus, class, or 

 order to which they belong, a correct delineation of them may be 

 sufficient to enable us to identify them with objects found in other 

 coal-fields, perhaps in very distant parts of the world. 



The author adopted at an early period the opinion that " Strata 

 are characterized by their Fossils," and he appears to think, that 

 in the coal-field under his consideration, each bed of shale has 

 vegetable impressions of its own. By the precision with which the 

 work is executed, the justice of this opinion is at once put to the 

 test ; the successive strata are numbered in regular order, and the 

 names of the plants (where they have names) are attached to the 

 numbers to which they respectively belong. Now, in looking over 

 the list, with a view to the determination of the question before us, 

 I observe Stigmariafucoides at No. 25, 55, 223, 232 ; Sigillaria Or- 

 ganum at No. 37 and 118; Sigillaria oculata at No. 74 and 79; Aste- 

 rophyllites longifolia at No. 16, 330, and 370} and Neuropteris gi- 

 gantea at No. 1 12, 14-7, 249 a, and 406. 



A series of Vegetable Impressions transmitted to us by Mr. De 

 la Beche has given rise to a good deal of discussion. The plants 

 have been examined by Mr. Lindley, and identified at once with 

 those usually found in the Newcastle and other regular coal-fields ; 

 they form the roof of certain beds of coal or culm whjch have long 

 since been observed and worked in the neighbourhood of Bideford 

 in Devonshire, and extend from the shore inland to the distance 

 of about fourteen miles, being about three quarters of a mile in 

 breadth. Along the coast very distinct sections are exposed, both 

 of these beds and their associates. The associated beds have hi- 

 therto been generally referred, and with the utmost confidence, 

 to the transition epoch. Many of them appear to me identical 

 with those in the Hartz Mountains, to which the name of grauwacke 

 was in the first instance applied, and which may therefore be con- 

 sidered as the types of that formation. Mr. Smith, indeed, in his 

 geological map of England, refers the Bideford district to the red 

 and dunstone of Brecon and the south-east part of Scotland ; 

 whether he applies that term to the old red sandstone exclusively, 

 or to the old red sandstone and grauwacke conjointly, I do not 

 know ; at all events, neither he nor any other person has ever ex- 

 pressed a suspicion that the beds under our consideration may be 

 more modern than the limestone of Derbyshire; nor am I aware that 

 such suspicion is entertained even now by any one who has seen 

 them in situ. 



Mr. Ainsworth, an active naturalist, who is gone out with Cap- 

 tain Chesney on an expedition to the Euphrates, has published an 

 Account of certain Caves at Ballibunnian on the coast of Kerry. 

 In the bay which bears that name, the cliffs, which rise to the height 

 of a hundred feet, are composed of two beds (varying from thirty to 

 forty feet in thickness) of compact ampelite, divided by seams of 

 the same slate but fissile and anthracitous, and pouring out stream- 



