274 n. J. Loive — Devonshire Geology. 



assuming that tliey are of shallow sea and shore formation; that 

 the western border of the chalk and greensand deposits becoming 

 exposed, to tide, wave, and current action, was thoroughly disturbed 

 by these agencies, that the beds were worn down, sifted, and the 

 materials rearranged ; and that while subjected to these processes 

 some new material was being added from the shores and streams of 

 the bordering Dartmoor land in relative proportion to the distance 

 from that shore. 



Turning now to consider the plastic clay, sand, and lignite beds 

 which overlie a part of these gravels and form such a distinguishing 

 feature in the geology of the Bovey area, the first question that 

 presents itself in regard to them is, what relation, in time, do they 

 bear to the beds immediately preceding them in position? Were 

 these deposits laid upon the gravels without any material break in 

 time, alteration of conditions, or change of agency? The citations 

 are not definite upon these points, but as each writer attributes the 

 gravels and clays respectively to the agency of an eastward-flowing 

 Eocene river it would appear as though the later author had adopted 

 the river of the former, thus making the formations consecutive in 

 both position and time. In respect to the latter point there does 

 seem to be some doubt in the mind of Mr. Reid as to the exact 

 horizon of the clays in the Eocene series, for he writes : — " With 

 regard to the age of the lignite and pipeclay of Bovey it is difficult 

 yet to speak with confidence. Mr. Starkie Gardner has pointed out 

 that the flora is probably of Bagshot age, not Miocene as stated by 

 Heer, and the resemblance of the deposits and of their flora to the 

 undoubted Bagshot of Dorset is most striking. Still, one cannot 

 say that the botanical evidence is conclusive, for the species are few 

 and greatly need re-examination." ^ 



Now the gravels and clays bear no relation to each other in either 

 mineral constitution or origin, so that there does not appear any 

 acceptable way of reconciling these facts with the hypothesis that 

 the same river was responsible for both deposits. 



The supposition is rendered more untenable by the statement on 

 p. 271, anle, that " the complete absence of any material derived 

 from flint or chalk shows that no chalk ranges were cut through 

 by it, and the quartzose and granitic sand and pipeclays that its 

 sediment must have been mainly derived from an old rock area." 

 This provokes the query, how could that river flow from the west 

 in Middle Eocene times without going over and through Cretaceous 

 deposits ? 



But it is the exact mode of deposition of the Bovey clays, sands, 

 and lignites only that we are now considering ; their origin is so 

 evident as to be beyond dispute. The authors cited declare that 

 these beds do not form an independent deposit, but an outlier of 

 Eocene strata that formei'ly extended from Mid Devon to the Isle of 

 Wight. It should perhaps be noticed that Mr. Gardner does not 

 appear to be quite convinced as to the exact relation of the deposits 



1 Quart. Joui-n. Geol. Soc, 1898, p. 236. 



