Limestones of South Devon. 723 



mountain-limestones, and of an ancient rather than a recent date ": the fossils of Torquay, Petit 

 Tor, and the surrounding neighbourhood, are said to be for the most part similar, (pp. 38, 63.) 



Mr. De la Beche, in a Memoir on Tor and Babacombe Bays, states that the limestones rest 

 upon old red sandstone, and contain fossils which have been discovered in the carboniferous lime- 

 stone of other places. (Geol. Trans., 2nd Series, vol. iii. p. 163.) 



In the Transactions of the Plymouth Institution, is a paper by Mr. Prideaux, containing the fol- 

 lowing passage ; " Catdown and Teats' Hill are entirely limestone, which very soon after parting 

 from the slate assumes a reddish hue, from the presence of siliceous matter of that colour ; this 

 presently after appears in bulk in the character of the old red sandstone, alternating with the 

 limestone, south, though much less strikingly than the slate does northward." Mr. Prideaux also 

 observes. There is a marked diversity in the texture, position, and contained animal reliques of the 

 limestones, and that the eastern is probably older than the western ; referred by Mr. De la Beche 

 to the carboniferous series. (Trans. Plym. Instit. pp. 36 and 43, 1828-1830.) 



Dr. Boase, in his elaborate Memoir on the Geology of Cornwall (1830-1831), speaks doubt- 

 ingly of the age of the limestone on the west side of Plymouth Harbour, not having been able to 

 determine its connection with the greywacke. The strata of Cawsand Bay he states is generally 

 believed to be old red sandstone. (Trans. Geol. Soc. Cornwall, vol. iv. pp. 216, 218.) 



In all the editions of Mr. De la Beche's Manual (1831 to 1833), the limestones on the southern 

 side of Tor Bay are included in the greywacke series ; but the author considers it exceedingly 

 difficult, in consequence of the greywacke sometimes being undistinguishable from the old red 

 sandstone, to determine the age of those limestones of Southern Devonshire, which are much broken 

 by faults, greatly disturbed and contorted or much concealed by the new red sandstone (1st edition, 

 p. 438, and note, 1831 ; 2nd edition, p. 454, and note, 1832 ; 3rd edition, p. 420, and note, 1833). 



About the year 1833 appeared the valuable article on Geology in the Encyclopaedia Metropo- 

 litana, by Mr. J. Phillips. It contains extensive lists of organic remains, assigned to the pri- 

 mary (transition) class ; but the author leaves to future observers to determine whether the South 

 Devon limestones belong to the transition series (p. 574, 577). 



In the two first editions of the same author's Guide (p. 115, 1834 and 1835), the sedimentary 

 rocks of Devonshire are also placed in the primary class ; and in the 3rd edition (1836), their posi- 

 tion is not defined, it being only stated that some portion of North and South Devon belong to the 

 Cambrian System, and that much of the killas of Cornwall is not more ancient (1st edition, p. 115 ; 

 2nd edition, p. 129 ; 3rd edition, p. 140). 



In the abstract of a paper read in January 1836, by Mr. De la Beche, the whole of the grey- 

 wacke of Devon and Cornwall is said to be older than the Silurian formations. (Geol. Proceedings, 

 vol. ii., p. 225.) 



In a Memoir on the country between the Ex and Berry Head and Dartmoor and the coast, 

 read May 1836, Mr. Austen mentioned the transition rocks as containing beds of limestone rich 

 in organic remains. (Geol. Proceedings, vol. ii. p. 414.) 



It was at the Bristol Meeting of the British Association, August 1836, that Prof. Sedgwick 

 and Mr. Murchison read their first memoir on the structure of Devonshire, in which they proved, 

 for the first time, that the culm-measures of the central part of the county are newer than any of 

 the stratified groups associated with them, and of the age of the carboniferous series ; and tliough 

 they did not describe the country south of Dartmoor, yet the calcareous rocks of that district 

 were considered to be on a parallel with the lowest division of the North Devon series, or in the 

 middle division of the Cambrian System. The same view is maintained in the paper read to tliis 



VOL. V. SECOND SERIES. 5 A 



