A. Champernowne — The Devonians of N. and 8. Devon. 197 



I would also reason thus : — If we carry a formation, some thou- 

 sands of feet thick, at a high angle, to an unknown depth, we are 

 .bound to show that it comes up again somewhere in some form or 

 other, unless where a whole kingdom is masked by transgressive 

 rocks, it may be Mesozoic or newer rocks. So, conversely, if the 

 Staddon sandstones, with southerly dip, have swept over the Ply- 

 mouth limestone and come down from the sky, where did they 

 go up ? The Pick we II Down sandstones qo down south, under 

 the Culm trough, so that will not do. 



But if the Staddon beds are simply rucked up, and the curve 

 cut away, then, in all probability, they would themselves be the 

 equivalents of the Pickwell Down beds ; and similar reasoning would 

 apply to the latter in reference to the Hangman beds further north. 



It makes no difference to the argument whether the group is 

 everywhere continuous over the mineral axis of the two counties. 

 But that sandstones and quartzites, whether red or no, do underlie 

 the killas in some districts south of the Culm Measures, the St. 

 Breock's anticlinal west of Bodmin clearly shows. 



As far as I have gone hitherto, the evidence is, to my mind, all in 

 favour of Jukes's views, if only for " great fault " we substitute 

 '•' inverted anticlinal," his alternative hypothesis : showing, in short, 

 that while the amount of disturbance is well-nigh incredible, the 

 original order was comparatively simple. 



Again and again, formerly, have I returned home perplexed, 

 utterly unable to decide whether I had been working in upper or 

 lower slates, so contradictory was the evidence. One quarry, that 

 of Englebourne, where occurred in fair preservation fossils^ like 

 those of Wissenbach, Bundenbach, etc., deep below the Eifel lime- 

 stone, came within a tract shaded on Dr. HoU's map " Upper South 

 Devon " ! 



But since I have come to regard the Devonian slates in their 

 entirety as one system, though most complex, with grits prevailing 

 in the lower part, and limestone bands in the upper ; now filling 

 the whole space from Old Eed to Coal Measures, the limestones 

 only nodular or absent, and anon, as these bands come in and unite 

 into masses of a thousand feet and upwards, dwindling away into 

 mere passage-beds : — since then, I say, it is marvellous how one 

 point after another, which before had been all obscurity, has flashed 

 into the broad light of day. 



It is useless to think of carrying on a field survey by means 

 of continual appeals to the fossils : on the other hand there are, 

 of course, innumerable instances where beds may be thus absolutely 

 identified, especially where a formation (such as the Lias for in- 

 stance) maintains its homogeneous characters over wide areas. 

 This, however, the formations which intervene between the Upper 



logical Survey) have laboured successfully in this field. I hope on some future 

 occasion myself to describe a new area of Culm shales and grits resting in perfect 

 conformity on Devonian limestones. 



1 A selection of these are, at this moment, in the Editor's hands for deter- 

 mination as far as possible. 



