Notes and Comments. 329 
through rock and drift, and in resorting and redepositing the 
debris, seems quite sufficient to account for the complicated 
superficial deposits in this area. 
ONE GLACIATION. 
No evidence has been found of more than one period of 
glaciation nor of any local glacier system. There are, however, 
curious corrie or cirque-like features, e.g., on Shelf Moor, 
Glossop. Moreover, although the Pennines are on the whole 
much lower north of the Etherow Basin than further south, 
the overflow-channels of glacier-lakes can be found at higher 
altitudes in the former than in the latter region. This is the 
reverse of what might be expected if the higher ground were 
ice-free. It may be, therefore, that at and near the time when 
the ice-sheet attained its maximum development, the snow-line 
actually descended below the altitude of the higher Pennine 
hills, and, without bringing about a definite local glaciation, 
temporarily filled the higher hollows with snow up to the 
general level of the ridge. Thus, instead of the margin of the 
ice-sheet at that stage melting away rapidly, melting might be 
considerably reduced and even temporarily suspended, and the 
ice-sheet reinforced by the local snow-fall. Such conditions 
would tend to depress the limit of distribution of erratics 
immediately west of the highest ground, but where an ice- 
stream, carrying erratics actually crossed the watershed, they 
might lead to the distribution of those erratics further and 
more widely than otherwise might have been possible. 
THE CARBONIFEROUS LIMESTONE ZONES 
Dr. Albert Wilmore stated that the sequence is well seen in 
the neighbourhood of Clitheroe, where numerous quarries 
have been opened up. The lowest beds exposed are near 
Chatburn Hill, and are dark, thinly-bedded limestones with 
calcareous shale partings. Fossils are very scarce. There is 
a great thickness of these almost unfossiliferous beds, the top 
parts of which are dolomitic. Bold Venture Quarry, Horrocks- 
ford Quarry, and several other exposures show beds in probably 
Lower C. with numerous small Zaphrentids (chiefly Zaphrentis 
omaliust, with the variety ambigua of Mr. R. G. Carruthers 
very common). Higher parts of these beds contain Caninia 
cylindrica, which has been found at Brungerly Bridge, in Bold 
Venture Quarry, at Pimlico, and at Downham. This species 
is not so common or well-developed as in beds farther east, 
towards Hellifield and district. Among the brachiopods are 
Chonetes comoides, Orthotetes crenistria, etc. Large gasteropods 
such as Euomphalus pentangulatus and Bellerophon cornuarietis 
are common. Conocardium Iibernicum is a_ characteristic 
lamellibranch. Above these beds come the lowest beds with 
Productus sub-levis, and the Knoll beds of Coplaw, lower part 
1915 Oct. 1. 
