434 Dr. Nils Olof Hoist — The Ice Age in England. 



They are not so high, but otherwise of the same size and shape, as 

 the tubercles on L. conferta, and they also coalesce together. In the 

 few specimens I have been able to examine, I have not found any 

 summit-apertures on the tubercles. The rings of the base are -£mm. 

 wide. The radial pillars of the caenosteum, which have a diameter of 

 •J- mm., traverse each ring, in the direction of its width, before 

 turning to the upper surface, and give the appearance of regular 

 radial ridging. 



It seems to be of rare occurrence, as through the kindness of 

 Mr. H. Woods and Mr. H. A. Allen I have been able to ascertain 

 that there were none in the Sedgwick Museum, Cambridge, nor in 

 the Museum of Practical Geology, Jermyn Street. (I have been able 

 to supply the latter.) 



I am also much indebted to Mr. W. D. Lang, at the British Museum 

 (Natural History), South Kensington, for the help he has given me. 

 The specimen, figured by Nicholson, is at this Museum, but the place 

 of origin stated, the Wren's Nest, Dudley, is doubtful. It is much 

 more likely that it came from the Much Wenlock district, as also did 

 the other small specimen in the Museum. For these reasons I would 

 make this a new species with the name Labechia rotunda, taking as 

 the type the specimen figured on Plate XV, B, which was found at 

 Shadwell Rock, Much Wenlock, Shropshire, and which I have 

 deposited in the Geological De'partment of the British Museum 

 (Nat. Hist). 



II. — The Ice Age in England. 



By Dr. Nils Olof Holst (late of the Geological Survey of Sweden). 



(Continued from the September Number, p. 424.) 



AFTER the little survey of the pluvial epoch contained in the 

 preceding section we may turn our attention again to England. 



In the Thames Valley at Swanscombe (Barnfield pit) there is found 

 beneath the deposits which yield early Chellean implements l a yet 

 older layer which does not contain any implements. 



Still somewhat younger, according to A. S. Kennard, is the 

 so-called Neritina locality at Swanscombe. This, no less than the 

 other, is of undoubted pre-Glacial age. Starting from this we may — 

 thanks to the researches of the British palaeontologists, and perhaps 

 especially malacologists — construct a little series of other similar 

 pre-Glacial occurrences in the following order from older to younger, 

 all from the lower part of the Thames Valley. 



1 . Swanscombe, Neritina locality. — Characteristic molluscs : Neritina 

 grateloupiana, Valvata piscinalis, var. naticina, 2 and Vivipara \_Paludina~\ 

 diluviana, which are all wanting in the following younger localities. 



2. Grays. — Valvata- piscinalis, var. antiqua. This is wanting in the 

 following. 



1 Elephas primigenius, which is quoted as occurring in Barnfield pit, is 

 really E. antiqims, the elephant characteristic of Chellean deposits. 



2 The statement that this mollusc is also found at Crayford depends upon an 

 erroneous determination. 



