Geological Society of London. 187 



numerous exposures of rounded gravel and stratified sand between 

 the north end of Minera Mountain and Llangollen Vale, which, in 

 some places, spread out into large flat expanses, but more frequently 

 assume the form of knolls (frequently in perched positions), which 

 rise up from beneath a covering of clay or peat. He dwells on the 

 probable origin of the knoll-shaped configuration, including the 

 theory' of the precipitation of the drift from the stranding of fioating 

 ice, and the forcing up of previously deposited drift by the same 

 agency, but inclines to the idea of the knolls having been chiefly 

 accumulated by sea-currents. The author then describes several 

 large areas in North Wales in which he could find no trace of 

 rounded gravel, enters into a consideration of the causes of these 

 driftless areas, and discusses the relative merits of the theory of 

 their having been temporarily occupied by land-ice, and of the 

 theory of non-exposure to tempestuous seas, or seas capable of 

 rounding stones. He then gives an account of the discovery of 

 granite boulders, associated with partially rounded drift, on the 

 summit of Moel Wnion, 1900 feet above the sea (near Aber, North 

 Wales) ; and endeavours to show that, while they could have been 

 readily transported by floating ice (probably from Scotland, certainly 

 not from Cumberland), the flow of land -ice from Snowdon, according 

 to Ramsay, along the north face of Moel Wnion, must have prevented 

 the access of northern land-ice to the summit of the latter mountain, 

 while land-ice flowing from Cumberland to Anglesey (according to 

 Ramsay) could not have been crossed by land-ice flowing south from 

 Scotland to Moel Wnion. After referring to the outward direction 

 of strias on the north coast of North Wales, he concludes by giving 

 a summary of facts and inferences. 



2. " On some Sections of Lincolnshire Neocomian." By H. Keep- 

 ing, Esq., of the Woodwardian Museum, Cambridge. Communicated 

 by W. Keeping, Esq., M.A., F.G.S. 



The construction of the Louth and Lincoln Railway, in the year 

 1872, led to the exposure of some fine sections of the Neocomian 

 strata forming the base of the Lincolnshire Wold. From these beds 

 the author had obtained a very large number of fossils, in many 

 cases in an excellent state of preservation. As the sections are now 

 becoming obscure, the author gives an account of the observations 

 made by him at the time when they were best exposed, with lists 

 of the fossils he obtained from them. He agrees with Professor 

 Judd, who in 1867 first described these strata and determined their 

 age, in his conclusions concerning the classification and correlation 

 of the beds, but is disposed to regard the sands above Market Rasen 

 as being a drift deposit, and not as belonging to the Lower Sand and 

 Sandstone. 



3, " Notes on the Geology of the Cheviot Hills (English side)." 

 By C. T. Clough, Esq., M.A., F.G.S. 



After a brief description of the physical structure of the district, 

 the author passes on to its igneous rocks. These he groups under 

 three heads — (1) the granite, (2) the lava flows and ash beds, (3) 

 the intrusive dykes. The first occupies an area of about 24 square 



