758 SIR HENR^ II. HOWORTH ON THE [Nov. 9, 



mollusca from the marine alluvia of those portions of the Essex 

 inlets which have silted up, except an occasional Scrohicularia. In 

 their paper on the new dock excavation at Southampton in 1889, 

 Messrs. Shore & Elwes give a list of the marine shells found in 

 the estuarine mud there, which they say are similar to those of the 

 numerous mud harbours on the south coast of Hampshii'e. The 

 list includes 15 lamellibranchs and 23 gasteropods, but the Myas 

 do not occur in it (Proc. Hants. Club, pp. 49, 50). 



In the estuarine deposits at Rhyl the only shells found were 

 Scrohicularia piperata and Pholas Candida (see Survey Mem. 

 Rhyl, (fee, p. 41). 



The evidence is the same from tl e marsh and fen deposits 

 of Lincolnshire, from which Scrohicularia piperata, Ostra;a edidis, 

 Cardium edide, Tellina solidida, Solen siliqua, Fusus antiquas, 

 Purpura lapillus, Littorina liiorea, Mtirex erinaceus, and Trochus 

 cinerarius have been forthcoming, but not Mya arenaria (see 

 Memoir on the Map of East Lincolnshire, pp. 105-111). 



The same is true of the estuary of the Humber, in the alluvium 

 and warp of which we find Scrohicularia piperata, Tellina soli- 

 dula, Cardium edule, Littorina litorea, and Hydrohia, but not Mya 

 arenaria (Ussher & Reid, Memoir on Sheets 86, 185, and 189). 

 The same is true a,gain of the estuarine deposits in the Firth of 

 Forth, More interesting because much more extensive are the 

 similar Fen deposits round the Wash. 



The Wash is clearly the shrunken remnant of what was 

 foi-mei-ly a great arm of the sea occupying the greater poition of 

 the Fenlands, which has been gradually silting up for a long 

 period by deposition of marine alluvium, and, as Skertchley 

 showed, is in no way a delta deposit. In the now enclosed and 

 desiccated parts of the primitive Wash, Skertchley divides the 

 surface-deposits into what he calls Fen gravels and alluvium. He 

 gives several sections of each, and in his list of the marine shells 

 found in the Fen gravels the Mya does not occur. The alluvium 

 he divides into two kinds — namely, clay and warp. In the clay 

 he describes finding Scrohicidaria piperata, many in single valves, 

 but a fair average with both valves in situ; a few shells of 

 Tellina halthica and dwarfed specimens of Cardium edtde, Mytihts 

 edulis, and Ostrcea edidis ; occasionally little Rissoas being plentiful. 

 " I have never," he adds, " found or seen a Mya or a Solen, 

 although they are common enough in the Wash, neither does the 

 Cyprina islandica occur, though it also lives in the Bay " (Survey 

 Memoir on the Fenlands, p. 176). 



On a later page, after giving a formal list of the fauna of 

 the inland silts, lie continues : — " The silt beds forming on the 

 shores contain the same species, but with the addition of Mya 

 are^iaria und Mya truncata, both of which are common" (ibid, 

 p. 182). This is surely a very interesting and notable fact, for 

 this warp and marine alluvium of the Fens is the only deposit 

 on a considerable scale in these realms whei'e the latest history of 



