162 DEPTH AND SUCCESSION OF THE BOVEY DEPOSITS. [May 1909. 



8. The Depth and Succession of the Bovey Deposits (Devon). By 

 Alfeed John Jukes-Beowne, B.A., F.R.S., F.G.S. (Read 

 January 27th, 1909.) 



[Abstract.] 



The total thickness of the Tertiary Beds in the Bovey Basin has 

 never yet heen ascertained, hecau.se no boring has yet reached the 

 bottom of the basin in which they lie ; and no one has yet 

 attempted to make out a stratigraphical succession from the 

 sections exposed in the numerous clay-pits. 



Some years ago, however, Messrs. Candy & Co., of the Heathfield 

 Potteries, put down a boring which reached a depth of 526 feet 

 from the surface. Having obtained some particulars concerning 

 the beds traversed by this boring, the Author is able to discuss the 

 succession of the Bovey deposits, so far as they have been explored. 

 The following is a generalized description of the strata seen in the 

 Heathfield pit, and penetrated by the boring from the bottom of 

 that excavation : — ■ 



Thickness in feet. 



Superficial deposits about 20 



Beds of clay and sand, with occasional beds of lignite 250 



Beds of lignite and clay, with one of sand 36 



Beds of lignite, with thin layers of clay 220^ 



526i 



The Author confirms the conclusion arrived at by Pengelly in 

 1861, with regard to the relative age of the beds exposed in the 

 ' old coal-pit ' south-east of Bovey Tracey and those proved in 

 a boring to the east of it. From all the data mentioned, and 

 assuming the actual base of the Tertiary deposits to be not more 

 than 30 feet below the bottom of the Heathfield boring, he 

 estimates the total thickness of the ' Eocene ' beds to be about 

 613 feet. 



The Bovey Basin itself is regarded as a tectonic basin or post- 

 Eocene centrocline, and not as a lake-basin ; although, during the 

 deposition of the higher part of the series, it may have formed part 

 of a large lacustrine or lagoon area, extending over the greater 

 part of East Devon. 



The Author dissents from Heer's view of the manner in which 

 the lignites were formed, discusses the identification of some of the 

 plants, and concludes that the lignites which form the mass of the 

 lower beds represent the growth and decay of successive swamp- 

 forests, similar to that of the Great Dismal Swamp of Virginia at 

 the present day. 



