TRANSACTIONS OF THE SECTIONS. 75 



Hue to the Yoredale series; that north of the Pennine escarpment the Scar lime- 

 stone series lost its distinct character and became quite indistinguishable from 

 the Yoredales, either stratigraphically or palteontologically ; but that the entire 

 set of beds between the Millstone-grit and the Tuedians in Northumberland re- 

 presented the entire Carboniferous Limestone series of the Midlands and Belgium, 

 and not onlj', as Prof de Koninck had lately stated, the Upper Division, or Calcaire 

 de Vise. The name " Bernician series " was proposed for the whole series having 

 a YoTeisle fades in Northumberland*. 



On the Geohgkal mmning of the term " liiver-hasin," and the desirahility of 

 suhsfituting "Drainage-area." By D. Mackintosh, F.G.S. 



The author believes that though field-geologists understand the meaning of the 

 word "river-basin," it is not only liable to convey a false impression, but has actu- 

 ally induced many geographers to represent watersheds as almost invariably run- 

 ning along the higher ground ; and, as a consequence, mountain-chains are repre- 

 sented as if they ran continuously along the lines of watershed or water-parting. 

 In most maps, so-called river-basins are represented as if they were really basin- 

 shaped ; but tlie author contends that there is scarcely such a tiling in nature as a 

 river possessed of an uninterrupted basin extending from end to end of its course ; 

 that in mountainous countries rivers either flow through ruined mountain-domes, 

 or what might be called inverted river-basins, or they traverse with equal indifier- 

 ence a series of basins and connecting narrow gorges. These basins are generally 

 oblong ; and in most instances the rivers cross them, not in the direction of their 

 length, but obliquely. He describes the ruined dome through which the Dee flows 

 in North Wales, and shows that the majority of the highest eminences are situated 

 not on the sides, but towards the centre of this so-called river-basin. He also de- 

 scribes the miscalled basins of the Wye in South Wales, the Taniar, and the 

 Bristol Avon. After recommending the word "drainage-area " a.s a substitute for 

 " river-basin," he concludes with an explanation of how mountains constituting 

 " lines of weakness " were either worn down into valleys or merely sawn asunder 

 by marine denudation, so as to leave a series of narrow gorges through which rivers 

 found their way to the sea. 



On the Origin of two polished and sharpened Stones f'om Cefn Cave. 

 By D. Mackintosh, F.G.S. 



The author entered particularly into a description and explanation of the peculi- 

 arities of form and polish presented by two fragments of limestone found in the 

 part of Cefn Cave where sand and sea-shells might still be seen clinging to the 

 roclty wall. One of the stones was axe-shaped, with a vei^ sharp edge, and an 

 intensely polished though only partially smoothed surface. Many reasons were 

 stated for arriving at the conclusion that the stones were first in the state of rocky 

 projections, roughly shaped by fresh water charged with carbonic acid gas — that 

 the subsequently polished surfaces and sharpened edges could not have resulted 

 from human agency, as they exhibited no indications of design, and could never 

 liave answered any human purpose — and that tliey were merely an extreme or ex- 

 ceptional result of some Idnd of natural agency. The author endeavoured to show 

 tliat the polished surfaces could not have been caused by the rubbing of cave 

 mammalia, as they occurred on both sides, and ran very nearly all round the spe- 

 cimens. In discussing the natural causes by which the stones were finally shaped 

 and polished, he showed that fresh water or a stream of water running only in one 

 direction could not have been the agent, and that the only adequate explanation 

 was to be foimd in the to-and-fi:o, recur^-ing, insinuating, and powerful action of 

 sea-waves. The author went on to show that the sea-waves must liave wielded 

 ijroken ice, that at the time the stones received their final polish the ice must have 



* Printed in eatenso in the ' Geological Magazine,' new series, decade 2, vol. ii. no. 11, 

 pp. 539-544. 



7* • 



