248 PKOCEEDINGS OP THE MALA.COLOGICA.L SOCIETY. 



crater-like hollows in the looser sand, and exposes the lacustrine 

 deposit at the bottom of the ' crater.' 



H. aspersa, next to Helicella barhara, is the most noticeably abundant 

 species. A large proportion have the light-brown periostracum so 

 peculiar in Iberian specimens. IT. nemoralis is not relatively so 

 abundant and does not occur at the 200-foot level, but seems confined 

 to some ' brambly ' dunes at a level about 50 or 60 feet higher. 

 There are very many thrush-killed H. asioerm and S. nemoralis lying 

 on the surface here. S. harhara is abundant everywhere. The 

 local name for these snails is ' sugar-loaves.' Mr. B. B. Woodward's 

 Helix nemoralis zone, above the rubble-drift, occurs at the north cliff 

 of Perranporth, overlain with many feet (4 to 7) of blown sand, 

 in which IT. harhara is abundant. Further work is needed round the 

 coast-sections. Large specimens of the normal variety of Arion ater 

 occur on the south cliff of Perranporth. A brown slug also occurred 

 on the Re Sands, probably Limaxfulva. The lacustrine Limnseas seem 

 to contain very dwarfed forms of Limncea stagnalis and Z. truncatula, 

 but some of the forms are so strangely unlike any modern Limnseas 

 that they may be undescribed, or if not, certainly abnormal, species. 

 The dwarfing of the species may be due to saline conditions, as 

 Mr. B. B. "Woodward suggests. It may be due to colder conditions 

 than now obtain, just as the dwarfing of Canadian specimens of 

 L.jugularis (identical with L. stagnalis) undoubtedly is. If further 

 work proves this latter supposition to be correct, it will corroborate 

 Mr. B. B. Woodward's most important paper in the Geological 

 Magazine last year^ as to the evidence of glacial conditions round 

 Newquay, of which district Perranzabuloe and Perranporth are parts. 



I. HoLOCENE, 



A. — The shells which I found in the walls of the ruined church were 

 Vitrea radiatula, Limaxflavus, Limncea pereger (dwarfed form). 



B. — (i) Those from the lacustrine area were — 

 Livmcea truncatula. 



L. sp. («), narrower and more elongated ^hmi. fereger . 

 L. sp. IV), narrower and straighter ihsca. <pereger . 

 L. stagnalis. Dwarf specimens. 

 L. pereger. 



L. sp. \c), may be an abnormal L. pereger. 

 Helix aspersa. Undoubtedly belonging to this deposit, as 



they are in the same sub-fossil state. 

 H. nemoralis. All specimens from 200-foot level, stained 



with iron oxide, and with a thicker shell than recent 



specimens. 

 Helicella virgata. Two specimens (same remark as above as 



to their state, v. H aspersa). 



Drift and Underlying Deposits at Newquay, Cornwall " : Geol. Mag., n.s. 

 dec. V, vol. V, January and February, 1908. 



