506 REPOET— 1882. 



Pecten polymorphus, Bronn. — Lisbon, Mediterranean, very rare fossil in Italian 

 and Sicilian beds. 



Tapes decussata, ranges south but not north of British Islands. Common in the 

 Mediterranean. 



Lutraria rugosa. — Algeria and Morocco (living), also Canaries. South of 

 Spain and Portugal. 



Syndomnya JBoysii (Amphidesma).— Atlantic ; rare ; ranges to coast of Spain. 



Pholas crispata, Linn. — Rare on south coast of England, a Scandinavian species, 

 and is found in the Crag. 



From ' the assemblage of moUusca, and the patch of Pholas crispata in conjunc- 

 tion with conditions of the deposit, we may infer that the relation of the land to 

 sea-level was then much what it is now, or that these ledges of mud-beds in which 

 this shell is found, then lay between tides.' Many of the bivalve moUusca 

 (Pelycipoda) lived in and on this mud, which is evident from the position in which 

 the shells are now foimd, especially the Mya, Lutrarice, and Pullastra (Tapes). 

 * This area,' according to the views of Mr. Godwin- Austen, ' must have been an en- 

 closed salt-water lagoon. The list of shells must be considered a special one, the 

 result of local conditions subordinate to, but indicative of, a much larger marine 

 fauna which had its fuU development in some adjacent sea ; and this fauna as a 

 whole differed as much from that of the present Channel waters, as the fossil con- 

 tents of the Selsea mud-deposits do from the mollusca now inhabiting the series of 

 large creeks and lagoons extending from Fareham to Pagliam.' As regards the 

 molluscan faima of Selsea, some of which, now found on the Sussex coast, are es- 

 sentially southern and western, they do not range further north , or into the German 

 Ocean area, and this southern relation of the fauna of the Lower Selsea deposit 

 (^Lutraria tnud-deposit) is further strikingly illustrated by the presence of the before- 

 mentioned two remarkable species, Pecten polymorphus BXiA Lutraria »*m<70S(7, neither 

 of which are now known to range further north than Lisbon. ' We therefore have 

 indications of a warmer condition of the waters of the English Channel, which 

 allowed southern forms to range to a more northern latitude than now, and then 

 a limitation of these forms to the area where now found, or in the Sussex deposits.' 

 The inference drawn by Mr. Godwin-Austen as to the manner in which the ele- 

 phant's remains occur in this Lutraria clay is an ob^-ious and an interesting one, as 

 it enables us to arrive at a relative geological date, showing that the lower estua- 

 rine beds of Selsea and of the Sussex levels generally were contemporary with what 

 is known as the period of the large mammalian fauna. 



Overlying this Lutraria or mud deposit, there occurs a tough, calcareous, sandy 

 clay, with chalk, and chalk flints — waterworn and of large size. This Yellow 

 Drift clay is of marine origin, determined by the associated mollusca ; Littorina and 

 Mytilus being disseminated through the mass. This deposit occurs over the whole 

 of the Selsea peninsula, and extends inland beneath the Sussex levels. Besides the 

 large masses of hints and materials from the chalk, oolitic rocks, and chert-sandstone 

 from the Upper Greensand, resembling that occurring at Lyme and Charmouth, there 

 are other rocks which, from their ' ages, composition, origin, size, and condition,' 

 render the mode of accumulation a problem of great geological interest. ' The rocks 

 in question consist of grey porphyritic granites, red syenites, syenite, homblendic 

 greenstones, mica-schists, green fissile slates, masses of quartz from veins, siliceous 

 sandstones,' such as occur in the Palaeozoic series (Lower Silurian) of Normandy, 

 micaceous sandstone with orthides, probably from the Devonian beds, and blocks 

 of compact limestone, whether from the Devonian series of Devon or the Cotentin 

 (France), is uncertain.' 



In size these older rocks range from coarse shingle up to masses of 20 tons 

 weight, the granitic rocks being the most numerous and of the largest dimensions. 

 A mass of porphyritic rock was exposed near Paghatn by coast -line denudation, 

 measuring 27 feet in circumference. Whence came they, and how brought, or 

 what the transporting agent beyond that of iloating ice, we know not. I must 

 refer you to Mr. R. Godwin-Austen's original paper for matter of the highest 

 interest relative to the origin and history of the yellow clay and the conglomerate 

 bed, and later deposits in Sussex, as well as other phenomena bearing upon the 



