Breccias and Physical Geography of their Age. 41^ 



from the east or north, but from inland ; and not from so far 

 inland as the Coalfields. Their sources therefore lie on a limited 

 belt, bordering the Boulder-Clay area. 



With this agrees the evidence of the included bonlders as a 

 whole. 



2. ' On the Eelation of certain Breccias to the Physical Geography 

 of their Age.' By Prof. T. G. Bonney, D.Sc, LL.D.* F.K.S., F.G.S." 



The author has endeavoured in this paper to collect from pub- 

 lished accounts and his own observations the evidence which certain 

 well-known and important beds of breccia afford, as to the physical 

 conditions prevalent when they were formed. First come sketches 

 of the principal breccias in the Bothliegende, the brockrams of the 

 iSorth-west of England and similar deposits in Armagh, the breccia- 

 beds of the Midlands and of ."Devon, and those of the ThiiringerwalcL 

 The fragments in these vary from angular to subangular, are some- 

 times interstratified with beds of finer material, sometimes are 

 themselves slightly stratified. They form marginal fringes to old 

 land-masses, from which we may, with more or less certainty, infer 

 them to have been derived, and are sometimes found to extend 

 outward from them, wedge-fashion, for a few miles. They appear.. 

 for reasons given, to have been the products of bare rocky hill-slopes 

 rather than of moantain-torrents. Floating ice has been suggested 

 as a means of transport, though the idea that the Cient and Enville 

 breccias indicate the former existence of glaciers is not now gene- 

 rally accepted, Mr. TTickham King having shown the materials to 

 have been derived from land-masses in the neighbourhood, and 

 Mr. P. D. Oldham having pointed out their resemblance to certain 

 Indian breccias. 



The so-called Dolomitic Conglomerate of the South-west of England,, 

 which exhibits similar characters, though on a smaller scale, and 

 the remarkable breccias in the Upper Oolite of Caithness described 

 by Prof. Judd are next noticed, after which the author passes- 

 011 to the breccia-beds in the Alpine Flysch, taking as examples 

 those of the Habkerenthal and of the Tal des Ormonts. The 

 former apparently are more sporadic in character, and are suggestive 

 of the intervention of floating ice ; the latter are more regularh* 

 interbanded, and that with true marine deposits : their occurrence 

 is extremely difficult to explain, without assuming the existence of 

 a mountain-range or a great highland district in their immediate 

 neighbourhood. 



When we seek for parallels to these breccias in deposits of late 

 date or in process of formation, we find some resemblances to them 

 in the breccias of Gibraltar described by Sir Andrew Ramsay and Prof. 

 James Geikie, in the stone-rivers of the Falkland Isles described by 

 Sir AVyville Thomson, and in the breccias of Persia and other parts 

 of Central Asia described by Dr. Blanford. The author accordingly 

 infers the Bothliegende (and probably the Triassic) breccias to be 

 indicative of a Continental climate, due to a great extension of land 

 or more probably the existence of a mountain-region on the west — 

 winters with severe cold and snow, but rather hot and arid summers. 



