W. A. E. Usshcr — Pleistocene Geology of Cornwall. 309 



of the blown sands, here consisting of rather fine buff sand, made 

 up of a mixture of quartz grains with comminuted shells, intersected 

 by numerous dark bands near the top, apparently dipping northward 

 at 10°, as though caused by the successive entombment of rank 

 grass surfaces under gradually accumulating sand. Below the dark 

 bands the sand still presents an appearance of bedding, such as 

 might be occasioned by successive slips from an eminence, wherever 

 the slopes became too sharp for the accumulating sand to rest. 

 From this bedded appearance, and from the frequent linear distribu- 

 tion of perfectly preserved land shells, (b.) Mr. Edmonds (op. cit.) 

 considered that the sand in its gradual accumulation had buried the 

 latter " without ever completely covering the growing turf whereon 

 the animals were feeding or hybernating." 



c. Mr. Boase (T.R.GS. Corn. vol. ii. p. 142) says, "In some 

 places where the sand has been bored to a great depth, distinct 

 strata separated by a vegetable crust are visible; which seem to 

 indicate a succession of inundations at distant periods ; but it is 

 possible .... that this may be owing to a local shifting of the 

 sands, because in other places the like series of strata is not found." 



d. In a deep cutting in the sand, about a mile from the sea, Mr. 

 Edmonds discovered a nest of small land shells, 50 feet from the 

 surface, of the following species : — Helix virgata, Zonites radiatidus, 

 Bidimus acidus, H. pulchella, Zua lubrica, Vertigo edentida, Pupa 

 marginata, P. umbilicata, P. anglica, Bithinia ventricosa. 



He gives the following list (T.R.G.S. Corn. vol. vii. p. 71) of shells 

 found under the surface of Phillack Towans (those marked with an 

 asterisk are now living within 10 miles of Penzance). 



Vertigo edentula. 



Bidimus acutus. 



obscurus. 



Carychium minimum. 

 Clausilia biplicata. 

 Conovulus bidentatus. 



denticulatus. 



Helix aspersa. 



caperata. 



ericetorum. 



Helix fulva* 



fusca. 



■ — — hortensis. 



nemoralis. 



pulchella. 



virgata. 



Pupa anglica. 



marginata* 



umbilieata. 



pygmma.* 



Vitrina pellucida. 

 Zonites alliarius. 



cellar ius. 



nitidulus. 



pygmceus. 



rotundatus. 



Mr. Edmonds mentions the occurrences of numerous shells of 

 Helix pulchella, at depths varying from 1 to 30 feet, in various parts 

 of the sands, and says that living specimens have been observed, 

 and that their exuviae have been found in Whitesand Bay sandhills 

 as well as those near Gunwalloe and Mullion, Mounts Bay, and 

 Gorran (on the South Coast of East Cornwall). 



Mr. Crouch, who identified the species given above, observes that 

 Helix pidchella is uncommon in the locality, that it has been found 

 by him near Falmouth, at Pendennis ; and near Penzance, at Tre- 

 reife ; also near the Land's End. 



From the quantity of shells found in so small a space in the 

 Towans, Mr. Crouch considers that they were once abundant in Corn- 

 wall, but are now gradually becoming extinct. 



Pupa marginata and Bithinia ventricosa he alludes to as rare, a few 

 dead shells having been obtained by him at Whitesand Bay (Land's 



