Geological Society. 397 



of Linton; 2. Foreland and Dunkerry sandstone; 1. Cannington 

 Park limestone. Only 9. 8. and 7. are described in the paper; the 

 other six, confined, the author believes, to the north of Devonshire 

 and the south of Somersetshire, being reserved for future consi- 

 deration. 



9. Floriferous slates and sandstones. — This term is proposed for the 

 series of beds containing culm, to avoid the ambiguity of the word 

 " carbonaceous," and as preferable, in the author's opinion, to 

 " culmiferous," plants being very generally distributed, and culm 

 confined to a small area. The sandstones are finely micaceous, 

 tough, externally of a rusty or dull purple colour, and internally of a 

 dull olive, and they are stated to be totally distinct from any others 

 in the country. The shales or slates are commonly dark-coloured 

 and friable, but at Forrabury and Bos Castle they constitute roofing 

 slates, resembling those of the inferior groups, though much dete- 

 riorated by a combination of pyritous anthracite. One variety, called 

 Adder Limestone, is a fine hone slate. The culm forms great insu- 

 lated elliptical " bunches," sometimes gradually thinning out, and 

 sometimes being suddenly nipped off. The strata are strangely 

 contorted, and these disturbances have entailed on the country its 

 physical features of rapidly succeeding hills and valleys ; but Mr. 

 Williams conceives, that the curvatures are confined to No. 9. 

 and the two upper divisions of No. 8. and that they are due to 

 lateral pressure produced by the upheaval of the granite of Dart- 

 moor. The area occupied by the "floriferous deposit" is stated 

 to be .50 miles in a west and east direction, and 25 in a north and 

 south. 



8. Coddon Hill Grits. — On the confines of this formation the 

 floriferous sandstones become thin-bedded and coarsely laminated, 

 and after a series of alternations and gradual transitions, are finally 

 succeeded by the well-characterized Coddon Hill grits. This series 

 is divided by the aiithor into grits, limestones, and dark slates, con- 

 necting the floriferous sandstones (9.) with the trilobite slates (7.) ; 

 and Mr. Williams asserts, that more regular passages from one 

 system of beds to another cannot exist, there being no want of 

 conformity, and that as the constituents of one deposit gradually 

 decrease those of the other gradually increase. The grits are stated 

 to be lithologically distinct from any other in the country. They 

 are slightly calcareous, fine-grained, flinty, thin-bedded, and dark- 

 coloured, but often striped of diff^erent tints ; and from containing 

 e varying proportion of felspar, occasionally assume, on decompo- 

 sition, a resemblance to some of the harder chalks. The wavelite 

 of Devonshire occurs in these grits. The following localities are 

 mentioned where the passage from the floriferous strata into the 

 Coddon grits, and thence into the trilobite slates, may be advan- 

 tageously examined : the neighbourhood of Bampton, Morebath, 

 where the turnpike road to Hatchet intersects the grits — the back of 

 Swimbridge, four miles east of Barnstaple — Rumson Lane, a mile 

 south of Barnstaple, and Fremington Pill, below Pen-hill, on the 

 west of Barnstaple. Organic remains are very rare in the grits, 



