258 A. J. Juices- Browne — T/ie Bovey Beposifs. 



the basement beds of the series, as seen on the borders of the basin, 

 consist of sands and gravels, such a succession as that proved by the 

 boring is just the opposite of what one would expect. 



The marginal beds above mentioned are not shown on the published 

 map of the Geological Survey, because when the survey was made, 

 many years before the issue of the map, these gravels and sands had 

 not been separated from others of post-Eocene date. Mr. Woodward 

 informs me that they hope to remedy this omission, and to prepare 

 a new edition of the map in the course of this year. So far as I have 

 been able to ascertain, the basal gravels do not extend all round the 

 basin, but are principally found on its eastern and south-eastern sides. 

 On the eastern side, from Kingsteignton northwards to Bellamarsh, 

 there is a nearly continuous border of sand and gravel which appears 

 to pass westward under the clays and lignites which have been so 

 extensively worked near Abbrook, Preston, and Knighton. The 

 material is largely sand, but whether there is always gravel beneath 

 the sand has not yet been definitely ascertained, nor have certain 

 tracts of more recent gravel been separated from the older deposit. 



I think it will be found that the Eocene gravel is practically 

 restricted to this eastern side of the area and to the small subsidiary 

 basin south and east of Newton Abbot, while round the western half 

 of the main basin, i.e. that part which lies to the west of the River 

 Teign, the basement beds consist of sand, though in places (as at 

 Staple Hill) there are pebbles and blocks of chert in this sand. 



The succession proved in the boring is interesting from another 

 point of view, for it confirms the conclusion arrived at by Pengelly 

 in 1861 ' with respect to the relative age of the beds exposed in the 

 ' old coal-pit ' south-east of Bovey Tracey. The section recorded by 

 him as seen in this pit below the ' Head ' may be summarized as 

 follows : — 



ft. in. 



Beds of clay, sand, and lignite . . . . . 19 4 



Clays with three beds of lignite 



Fluck beds of lignite with thin clays 



Sand (11 feet) and clay (9 feet) below 



Alternating beds of clay and lignite . 



Thick beds of lignite with thin seams of clay 



117 8 



From the information communicated by Mr. J. Divett, who then 

 owned this pit, Pengelly showed that a fault must cross the area to 

 the south-east of the exposure. At the old engine shaft 112 yards 

 east of the pit the succession proved (according to Mr. Divett) was the 

 same, but 140 yards further east he made a boring in 1855 to a depth 

 of 99 feet, and traversed a very different set of beds. These consisted 

 of sand and clay in alternating beds, with only one thin layer of 

 lignite, the clay beds varying from 3^ to 10 feet and the beds of sand 

 from IJ to 13 feet in thickness; the total thickness of sand is 47 feet 

 and that of clay about 39 feet. 



1 See the memoir by Pengelly & Heer, Phil. Trans, for 1862, and issued 

 separately as a volume entitled The lignite of Bovey Tracey, 1863. 



i 



