GG report— 1877. 



The foregoing Table will serve to show at one view the co-ordinations and theo- 

 retical conclusions to which the facts of Kent's Cavern have led me, as stated briefly 

 in the foregoing remarks. The Table, it will be seen, consists of two Divisions, 

 separated with double vertical lines. The first, or left hand, Division contains three 

 columns, and relates exclusively to Kent's Cavern, as is indicated by the words 

 heading it. The second, or right hand, Division is of a more general character, and 

 shows the recognized classification of well-known facts throughout Western 

 Europe. The horizontal lines are intended to convey the idea of more or less well- 

 defined chronological horizons ; and their occasional continuity through two or 

 more columns denotes contemporaneity. Thus, to take an example from the two 

 columns headed "Archaeological " and " Danish-Bog," in the second Division : the 

 horizontal line passing continuously through both, under the words " Iron " and 

 " Beech," is intended to suggest that the " Iron Age " of Western Europe and the 

 " Beech " zone of the Danish Bogs take us back about equally far into antiquity ; 

 whilst the position of the line under the word " Bronze," indicates that the " Bronze 

 Age " (still of Western Europe) takes us back from the ancient margin of the 

 Beech era, through the whole of that of the Pedunculated Oak, and about halfway 

 through the era of the Sessile Oak ; and so on in all other cases. 



On the Succession of the Palceozoic Deposits of South Devon. 

 By Arthur Champernowne, M.A., F.G.S. 



Opinion is still much divided on the vexed question of the older rocks of Devon 

 and Cornwall. General information on the history of the controversy may be 

 gained from Prof. Geikie's ' Memoir of Sir Roderick Murchison.' 



The writer (with others) holds that Jukes was right iu his main thesis, viz. that 

 the Devonian rocks are the general equivalents of the Lower Carboniferous, and not 

 the Marine equivalents of the Old Red Sandstone ; but that in his great fault theoiy 

 of North Devon he was mistaken, as Mr. Etheridge has apparent^ demonstrated. 



The South-Devonian area is perhaps more disturbed than any other equal area in 

 the United Kingdom. Inversions are very numerous ; but it is not always easy to 

 say what beds are inverted, and what are iu their normal position. To give purely 

 palseontological reasons appears to be reasoning in a circle, and some sort of rules 

 are necessaiy. 



If, for example, we are studying a band of rocks inclined in one direction, but 

 which we suspect is not intercalated between the beds on either side, and we 

 observe that the outer or bounding planes show a tendency to converge downwards, 

 the presumption would be that the mass is an inclined trough — if upwards, an in- 

 clined anticlinal fold. The simpler the fold the less liable we shall be to error. 



In applying these principles the author selects three areas for comparison, viz., 

 the Torquay Promontory, the tract south of Brixham and east of the Dart, and the 

 Plymouth district. 



In the Torquay district a series of Red Sandstones is undeniably subjacent to the 

 Great Devon limestone. It is believed that the Red Sandstones of the other areas 

 fall into the same horizon, and that together they represent the Old Red Sandstone, 

 the base of which is scarcely seen south of the Bristol Channel. 



Professor Phillips's section at Plymouth shows that the southern boundary of the 

 Plvmouth limestone is steeper by 25° than the northern (the former being 70° and 

 the latter 45°). 



Blue and grey fossiliferous slates &c. separate the limestone from the violently 

 contorted Red Sandstones of Staddon Point. 



^ The convergent dips of the limestone, together with the contortions of the 

 Staddon beds, points to the conclusion that the limestone occupies a trough, and 

 the Staddon beds are an inclined anticlinal, as Jukes also believed. 



Phillips held at that time that the superposition of beds on each side of the 

 Sound on the Plymouth limestone, "except by some improbable conjecture, could 

 not be shaken" (' Geology of Oxford and the Valley of the Thames,' p. 79), but he 

 subsequently modified this opinion. 



