Geological Society, 135 



of the Ribble, ranges an almost continuous line of argillaceous rocks, 

 generally fissile, and belonging to the third division of slates above 

 mentioned. This tract is bounded on the north by the elevated strata 

 that support the summits of Greygarth and Pen-y-gent ; and on the 

 south (in consequence of great dislocations) by millstone grit and the 

 coal measures. If the rivers Lune and Wharfe are included, no fewer 

 than nine streams cross the district from north to south, and exhibit 

 very distinctly the structure and relations of the rocks 5 the greater 

 number of the streams cutting through the limestone and millstone 

 grit, exposing the subjacent slate, and finally passing off on the de- 

 pressed strata of the coal measures. The author describes in detail, 

 the phenomena presented in these several sections, and illustrates his 

 observations by sectional views and sketches. 



The structure of the country is very well displayed in the course of 

 the Kibble, where the slate first appears on the north, beneath paral- 

 lel bands of limestone ; while on the south, the carboniferous 

 strata, of which the northern portion is horizontal, decline at a high 

 angle, thus indicating a vertical dislocation of about four hundred 

 feet. Besides this fault on the southern verge of the slate, another 

 still more important one may be traced in a parallel direction across 

 the valley of Ribbles-dale, and over Malham Moor 5 by which, strata 

 have been brought into opposition, that in their original place were 

 separated by a thickness of more than five hundred feet. Various 

 facts are stated by the author in proof of this derangement, and de- 

 scriptive of the phenomena produced by it. 



The author subjoins to his descriptions some remarks on the strati- 

 fication of slate, and on the difficulty of discriminating between the 

 planes of general stratification, or dip, and those of the cleavage ef- 

 fected by a blow, — the latter of which are often disposed at consider- 

 able angles to those of the dip. He is disposed to think, that in, the 

 fissile granular varieties of slate approaching to sandstone, the laminae 

 of cleavage may really be those of deposition j since the surfaces are 

 frequently coated with mica, and the fossil remains are in a disposition 

 parallel to them. Besides this more general cleavage, however, the 

 slate is also traversed by other planes, oblique to those of cleavage, 

 and less conspicuous, to which the quarry-men give the name of 

 " Bate." The direction of these planes, though nearly alike in limited 

 spaces, is found to vary considerably in different portions of the same 

 tract ; and even the better-defined planes of the ordinary cleavage are 

 seldom parallel to each other throughout any great extent of country. 



A collection of fossil vegetables, chiefly from the Jarrow and Fell- 

 ing collieries in the Northumberland and Durham coal-field, pre- 

 sented to the Society by William Hutton, Esq. of Newcastle-upon- 

 Tyne, with drawings describing the plants according to the system of 

 M. A. Brongniart, was accompanied with some remarks by the donor, 

 comprised in a catalogue. — The collection consists of Calamites, Sigil- 

 laria, Sagenaria, Stigmaria, Filices, Sphsenophyllum, Asterophyllum, 

 &c. j also several specimens of undescribed confervae, leaves, stems, 

 &c. 



A notice was read on the occurrence of "Chlorophseite" in basaltic 



dykes 



