H. J. Lowe — Devonshire Geology. 269' 



VI. — Old Lamps or New? Another Contribution to 

 Devonshire Controversial Geology. 



By Hakford J. Lowe, F.G.S. 



UNSOLVED geological problems, or what perhaps may be better 

 described as obscure points in geological history round which 

 conflicting hypotheses have arisen, are to be found in many parts of 

 our Islands, but Devonshire seems to be an usually prolific field for 

 them. Mr. W. H. Hudleston, F.E.S., in his presidential address 

 to the Devonshire Association in 1889, enumerates nine questions 

 propounded by Pengelly in 1868 as still requiring special con- 

 sideration in the future. Of these possibly three may be said to 

 have nearly or quite got beyond the controversial stage, but in 

 the meantime others have arisen, and it would thus appear that 

 the undecided position of numerous points demanding further in- 

 vestigation is the normal condition of a science in the developmental 

 stage. 



Evolution involves occasionally the disuse and reversion of organs 

 which formerly were of service, but the more general mode of 

 progress is by strengthening and more highly developing the 

 essential working parts so as to better fulfil their functions in the 

 more complex organism. 



Similarly, in the higher development of a science some early 

 working hypotheses must either be abandoned or modified to meet 

 further discovery and more widely extended correlations. _ The 

 earlier theory, however, is usually tenacious of the hold it has 

 gained by prior possession, and the newcomer must need not only 

 present credentials that will bear the closest scrutiny, but also 

 possess the irresistible power of simplicity and superior fitness in 

 order to gain the position it lays claim to. 



Now there is a time-honoured and simple theory respecting the 

 origin and formation of some peculiar deposits within the basin of 

 the Kiver Teign, whose right to possession of that small holding has 

 been called in question by several statements to be found scattered 

 among the geological records. No direct attempt has been made to 

 oust the old tenant and place another with a better title in its place, 

 but its position has been discredited by casual remarks and innuendo, 

 and its existence has been ignored when its territory has been 

 invaded by the explorer. 



We learn from one of our early masters, who is also regarded as 

 one of the keenest and most reliable of observers, De la Beche, that 

 within an area roughly defined as from a little south of Newton 

 Abbot to a little north and east of Bovey Tracey lie deposits of 

 lacustrine origin which now form a tract of level land traversed by 

 the streams Teign and Bovey, which presumably brought down the 

 material now filling up the lake depression formerly occupying this 

 part of their courses. In the master's own words — "From the 

 manner in which the Bovey deposit conforms to the valleys 

 adjoining it, the character of the clays and sands, and the greater 

 purity of the clays towards Kingsteignton and away from the granite 



