230 Geological Society. 



Magazine ' of January 1894, on the ' Three Glaciations in Switzer- 

 land/ in which the author described various glacial deposits near 

 the lake of Ziirich. He now describes a series of tluvio-glacial 

 conglomerates and interglacial lignite-deposits near the lakes of 

 Zurich, Constance, Zug, and Thun, which, together with, analogous 

 deposits at the base of the Eastern, Western, and Southern Alps, 

 constitute further evidence of two interglacial periods, and therefore of 

 three general glaciations, the oldest of these being of Upper Pliocene, 

 and the others of Middle and Upper Pleistocene age respectively. 

 As regards the origin, age, and the time required for the formation 

 of several of the Swiss deposits referred to in the paper, the author 

 arrives in several respects at conclusions differing from those recently 

 enunciated by others. The author also argues that the first inter- 

 glacial period was probably of shorter duration than the second; 

 and in confirming his former conclusion that every general glacia- 

 tion marks a period of filling-up, and every interglacial period 

 marks a period of erosion of valleys, he avers that, if this conclusion 

 be correct, it must needs be destructive of the theory of glacial 

 erosion. 



2. ' The Bajocian of the Mid-Cotteswolds.' By S. S. Buekman, 

 Esq., E.G.S. 



The Mid-Cotteswolds is defined as the district between the valleys 

 of the Erome and the Chelt. A description of twenty-five sections 

 is given, dealing principally with the strata found between the 

 Upper Trigonia-grit and the Upper Ereestone — such strata being 

 called, for the purpose of present distinction, ' the intervening beds.' 

 Of these twenty-five sections, seventeen, lying between Stroud and 

 Leckhampton, are discussed in Part I. of the paper to show the 

 succession of the intervening beds, to point out that Cotteswold 

 geologists have confounded two distinct deposits, the Lower Trigonia- 

 and Gryphite-grits, to prove that the former, and not the latter, is 

 the more persistent stratum, and to give evidence that denudation, 

 called ' Bajocian denudation/ has, prior to the deposition- of the 

 Upper Ti-igonia-giit, cut right through the intervening beds in the 

 neighbourhood of Birdlip, so as to make a shelving trough 6 miles 

 wide and about 30 feet deep. 



The remaining eight sections are described in Part II. of the 

 paper. They lie eastwards of Leckhampton, and are given to show 

 the discovery of another ammonitiferous horizon in the Cotteswolds, 

 yielding angustumbilicate Witchcllice. It is proved that this bed 

 is above the JNTotgrove Ereestone and below the Upper Trigonia- 

 grit ; so that it is really an addition to the stratigraphical sequence 

 hitherto recognized in the Cotteswolds. Its ammonites show it 

 to have been deposited contemporaneously wdth the middle of the 

 Sandford Lane Fossil Bed, and yet it is removed by 10 to 12 feet from 

 the Gryphite-grit = lower part of that bed. In the Mid-Cotteswolds 

 this important Witchellia-bearing bed is only preserved over an area 

 of about 1| square miles, because it has been mainly removed by 

 Bajocian denudation ; and only one side of one small quarry yields 



