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XXVIII. — On the Geology of the South-east of Devonshire. 

 By ROBERT ALFRED CLOYNE AUSTEN, Esq., F.G.S. 



[Read 1834, 1836, 1837, 1839, 1840*.] 

 Plates XLL, XLII. 



Introduction, p. 433. 



General view of the deposits of South Devon, p.434. 

 Actual period, p. 434. 



§ 1. Estuary deposits, p. 434. 

 § 2. River sand and gravel, p. 434. 

 § 3. Marine beds, p. 435. 

 Period prior to the most recent changes of re- 

 lative level of land and water, and of climate, 

 p. 437. 



§ 1. Surface-soil, p. 437. 

 § 2. Submerged forest-ground, p. 438. 

 § 3. Ancient alluvia, p. 438. 

 § 4. Ancient lacustrine deposits, p. 439. 

 § 5. Raised estuaries, p. 440. 

 § 6. Raised marine beds, p. 441. 

 Tertiary deposits, p. 442. 

 Period marked by extinct animal forms, p. 442. 

 § 1. Gravel, p. 442. 



§ 2. Ossiferous caves and fissures, p. 443. 

 § 3. Surface accumulations of higher levels, 



p. 446. 

 § 4. Uppermost beds of Haldon, p. 447* 



CONTENTS. 



Secondary Deposits, p. 449. 



§1. Chalk, p. 449. 



§ 2. Greensand, p. 449. 



§ 3. New red sandstone series, p. 453. 

 Carbonaceous Deposits, p. 457. 

 Strata subjacent to the Carbonaceous Deposits, 



p. 462. 



§ 1 . Coral limestones of Newton, &c., p. 463. 



§ 2. Red arenaceous slaty strata, p. 468. 



§ 3. Limestone of Yalberton, &c., p. 469. 



§ 4. Lower limestone of Ashburton, &c., 

 p. 469. 

 Igneous rocks, p. 470. 

 Earliest epoch, p. 470. 



§ 1. Interstratified, p. 470. 



§ 2. Intrusive, p. 471. 

 Carbonaceous epoch, p. 473. 



§ 1. Interstratified, p. 473. 



§ 2. Intrusive, p. 474. 

 Cleavage and jointed structure, p. 480. 

 Faults, fractures, and dislocations of strata, 



p. 482. 



Introduction. 



J. HE range of Dartmoor, independent of geological considerations, forms the most 

 natural division of the county of Devon ; and the following pages relate only to the 



* In this memoir are given in a condensed form the substance of the following papers : — 1. An Ac- 

 count of the raised Beach at Hope's Nose, read Nov. 19th, 1834. See Proceedings, vol. ii. p. 102. 

 2. On the part of Devonshire between the Exe and Berry Head and the coast and Dartmoor; read May 

 25,1836. Proceedings, vol. ii. p. 414. 3. On the Geology of the South-east of Devonshire; read 

 Dec. 13, 1837. Proceedings, vol. ii. p. 584. 4. On the Structure of South Devon; read April 24, 1839- 

 Proceedings, vol. iii. p. 123. 5. On the Bone Caves of Devonshire ; read March 25, 1840. Proceed- 

 ings, vol. iii. p. 286. 



