■Machintosh — Railway Geology in Devon. 393 



estuary of tlie Teign, proving that these are valleys of excavation, 

 and not of depression. Beyond Bishopsteignton the railway CTits 

 through what has been called Carboniferous slate passing into 

 limestone. The surface is here covered with gravel containing flints, 

 which may have come from Little Haldon, or from Milber Down on 

 the opposite side of the estuary. It would be very interesting to 

 obtain sections which would corroborate Mr. Godwin- Austen's state- 

 ment that a flint gravel extends under the Bovey formation farther 

 on, as this would prove the gravel to be of pre-Miocene age. A very 

 remarkable dej)Osit of regularly-stratified flints and sand has lately 

 been exposed near the summit of Woolborough Hill, south of New- 

 ton-Bushell, where Greensand is represented on the Ordnance Map. 

 The beds must originally have been horizontal, but they now dip 

 eastwards at a very high angle, showing that since their deposition, 

 considerable changes of surface-configuration, resulting from eleva- 

 tion or dej)ression, have occurred in this district. The above beds 

 appear to run under the Decoy clay and lignite, which are a southerly 

 extension of the Bovey formation, but this may be in appearance 

 only. 



The Bovey Formation.^ — On leaving Newton station for Bovey- 



1 The most recent writers on this formation are Mr. Pengelly, Mr. Key, and Dr. 

 Heer. The following is a very condensed statement of some of the principal facts 

 contained in Mr. Pengelly's paper read before the Royal Society, November, 1861. 

 The Bovey basin, exclusive of the part south of Newton, is four miles in greatest 

 breadth, and six in length. In the " Coal-pit" (about half-a-mile from Bovey) the 

 beds dip at 12|° towards S.W., the strike being N.W. and S.E. In Mr. Pengelly's 

 principal section there were 72 distinct beds of lignite, clay, and sand, including the 

 "head" or an unconformable covering, the thickness of which was 7|ft. The 

 upper series of beds (order descending) consisted of clay, sand (one bed of sand 

 6ft. Sin. thick and thinning out eastwards or along strike) ; many beds of clay and 

 lignite, one of the beds of clay containing lenticular patches of sand, most of them 

 containing fragments of lignite, and one bed of lignite 6ft. 2in. thick. Between the 

 upper and lower series there was a bed of sand about lift, thick, coarse in upper part, 

 finer towards base, containing patches of clay, and thinning out eastwards. Then 

 came the lower series of beds containing no sand, but consisting of many alternating 

 beds of clay and lignite, the former containing fragments of lignite. Towards the 

 base the beds of lignite were very close to each other, and the lowest 4ft. thick. 

 Some of the lignite beds consisted of, or contained, " board coal." Out of 27 lignite 

 or coal beds only seven were more than 1ft. 8in. thick. In some places rings of 

 annual growth of trees were seen pressed into ellipses. The beds are known to be 

 300 feet deep. A short distance E. of the pit, there is a fault running N,E. and 

 S."W., which proves a vertical displacement of the beds amounting to at least 100 feet. 

 The beds N.W. of this fault must have extended 100 feet higher than at present, 

 making the thickness of the deposit previously to denudation at least 400 feet. The 

 covering called "head," resting on the denuded edges of the beds beneath, con- 

 sists of sand and clay, with large and small stones of granite, metamoi'phic rock, 

 carbonaceous grit, trap, and flint and chert, the latter increasing in number eastwards. 

 No stones have been found under the "head." The Bovey beds must have been 

 accumulated in a lake ; the clay and sand must have come from Dartmoor ; and the 

 stones in the surface-covering must have been brought by a current from the north. — lu 

 a paper by Mr. Key, of Newton, read before the Geological Society in November, 1861, 

 it is stated that the " Bovey deposit " rises from under high tide level near Newton to 

 151 feet above mean tide on Knighton Heath. He mentions three parallel beds of clay 

 on the E. side of the basin, associated with muddy clay, silt, sand, and gravel, dipping 

 west. The clay beds thin out S. of Newton station, and occur again at the Decoy, 

 where they dip E.,and where several associated seams of lignite, parted by dark clay 

 and vegetable matter, stand nearly perpendicular. The pipe clay at the Decoy has 



