1861.] KEY BOVET DEPOSIT. 9 



Dennys, Esq., 3 Percy Terrace, Lower Road, Islington, were elected 

 Fellows. 



The following communications were read : — 



1. On the BoYET Deposit. By J. H. Key, Esq. 



(Communicated by Sir C. Lyell, F.G.S.) 



[Abridged.] 



Introduction. — Singailarly enough, as geologists approach our own 

 era the difficulty of detemiining the relative age of a particular stra- 

 tum generally increases ; and it is in the more modern tertiaries, or 

 deposits succeeding to these, that the greatest amount of difficulty 

 occurs. Among the strata not yet referred to any certain epoch, 

 but broadly designated " tertiary," are the clay-, sand- and lignite- 

 beds, known to geologists as the " Bovey deposit*." Having been 

 for the last ten years engaged in working and boring the various 

 beds of clay, I may have become possessed of facts not generally 

 known to geologists, bearing on the origin and nature of the deposit, 

 and which may assist in some degree to fix its relative age. 



The physical features of the basin. — The Bovey basin is a depres- 

 sion beneath the level of the surrounding country ; its length, from 

 Bovey-Tracey to about two miles south of Kingskerswell, is about 

 10 miles ; its breadth at the upper end about 2| miles, becoming 

 much narrower towards its southern extremity. Two rivers, the 

 Teign and the Bovey, both having their sources in the granite of 

 Dartmoor, run into this basin, meet above Stover, and fall into the 

 sea at Teignmouth. The Teign, the larger and more circuitous, for 

 about 13 or 14 miles before entering the Bovey basin, flows through 

 the slate ; and the Bovey River, rising near the centre of the moor, 

 crosses for a short distance the slate, and rims into the basin at its 

 upper end. All the drainage of the basin flows to the estuary of 

 the Teign through an opening between Buckland Point and Hackney, 

 about half a mile wide. 



The deposit, surroimded by hills forming the margin of the basin, 

 presents to the eye for the most part a level plain ; a large portion 

 immediately above the point where the Teign meets the tide being 

 of a very low flat character, subject to floodings at high spring- tides 

 and heavy rains ; fi'om this point it rises gradually, on the one hand, 



* The clays and lignites of Boyey-Tracey hare been more or less fully described 

 by Dr. Jeremiah Milles in the ' Pliilosophical Transactions ' for 1753 ; by James 

 Parkinson and Robert Scammell ('Organic Remains,' p. 123, &c.) in 1811 ; 

 C. Hatchett, Trans. Linn. Soc. vol. iv. p. 138, &c. ; and Phil. Trans. 1804, p. 390, 

 &c. ; J. Macculloch, Geol. Trans. 1814, vol ii. p. 18; Mr. Kingston, 'Mine- 

 ralogy of Teignmouth'; Conybeare and Pliillips, 'Outlines of the Geology of 

 England and Wales,' p. 328, and p. 346. 



A rSsume of the facts and opinions offered by the above-mentioned writers was 

 given by Mr. E. W. Brayley in Moore's ' History of Dcvonsliire,' 1829, vol. L 

 p. 380, &c. Further notices have been made by Mr. Godwin-Austen in 1834 and 

 subsequently (Geol. Proceed, vol. ii. p. 103, and Geol. Trans. 2nd ser. vol. xi. 

 p. 439, &c.); by Sir II. De la Beche in 1839 (Geol. Keport Devon and Corn- 

 wall, p. 24^3, &c.) ; by Dr. Hooker in 18.'>5 (Quart. Joum.Geol. Soc. vol. xi. p. 566) ; 

 and by Dr. Croker in 1856 (Quart. Journ. Geol. Soc. vol. xii. p. 354). -Edit. 

 Q. J. G. S. 



