680 Professor Sedgwick and R. I. Murchison, Esq., on the 



new red sandstone. So far we may state our grounds of conviction with un- 

 limited confidence. Neither can they be classed with any of the other forma- 

 tions with which they are associated; as has, we think, been sufficiently 

 proved in the previous portions of this paper. But in approaching the definite 

 question — what is the exact epoch of the culm-measures ? — we must fortify 

 ourselves with some more specific evidence, which might indeed have been 

 incorporated in the preceding general description, but which we have de- 

 ferred to this place, in order that the facts it offers might appear in a more 

 prominent form. 



In addition, then, to the thin carbonaceous bands above noticed, there are, 

 on the coast near Bideford, and extending from thence along the line of strike 

 far into the interior of the county, some much thicker bands of culm, which 

 have for many years been extensively worked. This fact was known by all 

 persons who had examined the structure of North Devon ; but we believe 

 Mr. De la Beche was the first who made the Society acquainted with vege- 

 table fossils, derived from these localities, sufficiently well marked to admit 

 of a botanical description or comparison with the vegetable fossils of other 

 formations. 



Near the coast, the culm appears to have been worked on two lines very 

 near each other; and on the north side of the culm beds is a very ferruginous 

 grit in a highly-inclined position, and exactly parallel to the culmiferous 

 shales*. When we visited the coast during the past summer (1836), they 

 were extracting no culm for domestic use ; but were working one pit, sunk, 

 we believe, on the southern line of culm, for the sake of a highly carbonaceous 

 and unctuous shale, which runs side by side with a thin band of pure culm, 

 and is extensively sold as a black pigment. 



The same culm beds have been traced eastward through the S.W. end of 

 Bideford ; and they were formerly much worked there in pits which are now 

 deserted. About two miles to the east of the town there have also been very 

 extensive works, which were partially re-opened last summer (1836), but 

 with what success we have not heard. At that place, there are three highly- 

 inclined beds of culm, designated by the names of south, middle, and north 

 veins, — all of which dip south. 



The south vein, or paint vein, is about three feet wide, and on its north side is a carbonaceous 

 shale, used for paint. The whole bed is very impure, and contains little good culm fit for burning. 



The middle vein is fifteen fathoms north of the former, and is about four feet thick on the 

 average, but expands, in some places, to twenty feet, and in. others is pinched out to a few inches, 



* See PI. LI., fig. 3. 



