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are slightly calcareous, fine-grained, flinty, thin-bedded, and dark- 
coloured, but often striped of different tints; and from containing 
@ 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, 
Mr. Williams having found only a few fragments of Crinoidea and 
a chambered univalve. 
The grits are associated, about the middle of the series, with 
large insulated lenticular masses composed of beds of dark lime- 
stones alternating with strata of black shale, containing plants and 
flakes of anthracite; also Goniatites and Posidonia. ‘These len- 
ticular masses may be traced, in the north of Devon, from Barn- 
staple to Bampton, and in the south from Launceston to Drew- 
steignton. To the east of Bampton and Drewsteignton the shales 
not only thin out, and the whole mass becomes calcareous, but the 
author says, that there is an upper suite of thick-bedded coral lime- 
stones. These changes are stated to take place at Hockworthy, 
Holcomb Rogus, Westleigh, Chudleigh, and Ashburton, emerging 
at each locality except the last, from below the floriferous slates, 
and accompanied by the Coddon Hill grits. At Ashburton, how- 
ever, he states, that a fault brings the limestone abruptly in contact 
with the trilobite slates, the passage beds not being exhibited. 
The Coddon Hill limestones are succeeded by the lowest division of 
No. 8, consisting of the series of slaty beds which forms the passage 
into the trilobite slates (No. 7.). 
7. Trilobite Slates.—This group is characterized, in some locali- 
ties, by an abundance of trilobites, particularly in the north of 
Devon, and at Landlake in the south. It constitutes the low 
southern flank of Exmoor, ranging from Baggy and Diamond Points 
on the British Channel eastward to Shawley; and Mr. Williams 
conceives that it constitutes the south of Devonshire and the whole 
of Cornwall, with the exception of the granitic and other igneous 
masses. The limestones of Trenalt, Petherwin, Landlake, Ply- 
mouth, Newton Bushell, Denbury, and Torbay, are placed in it by 
the author; but in the north of Devon he knows only two localities 
at which limestone has been observed in this division. Organic 
remains are abundant in the calcareous beds, and are well preserved. 
The author estimates the thickness of the group to be 84 miles. 
The strata in the north of Devon and south of Somerset inferior 
to No. 7, Mr. Williams proposes to describe in another paper. 
April 24.—James William Farrer, Esq., F.S.A., John-street, 
Berkley-square; C. B. Rose, Esq., of Swaffham, Norfolk; and 
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