DEAN AND JACKSON : CHARA AND SHELL-MARL AT HAWES WATER. I49 



were two forms of LiinncEa pereger, both small, one having a long 

 spire and the other a short one. Of Valvata piscinalis, the form 

 antiqua appeared to predominate, with occasional examples oi depressa. 

 The shells of V. cristata were only small, and could not be compared 

 with the specimens found by Mr. Welch in the shell-marl at Bally- 

 finragh Lough, Portaferry, Co. Down {Irish Naturalist, vol. ii, p. 46, 

 1902). Planorbis cristata occurred very sparingly, only about half-a- 

 dozen specimens were obtained from some pounds of material. 



Having looked through a large amount of literature bearing upon 

 the geology of this and adjoining districts, we cannot find that there 

 has been any previous attempt properly to investigate this deposit, which 

 is a matter for some surprise, considering that such a fine section is 

 available. The only exception is its mention by Mr. David Dyson, 

 in his somewhat scarce and little-known work,^ which runs as follows : — 

 " Haweswater, or Hazewater, is a small lake or tarn situate in the 

 township of Silverdale, in the parish of Warton, in the county of Lan- 

 caster. Its extent is about twelve acres, and its depth varies from 

 thirty to forty feet. The water is very clear, and without any admix- 

 ture of sea-water. The shells thrown up at the north side of the tarn 

 are all dead, without epidermis, but perfect in form, and purely white; 

 and there can be little doubt that living specimens exist in vast 

 numbers at the bottom of the water. The tarn is surrounded on all 

 sides, except the north, by peat-bog, which rests on a layer of shells 

 from two to three feet thick. A vertical ridge of rock forms the 

 northern boundary of the tarn, having a sloping beach formed princi- 

 pally of the detritus of the shell {Bithynia tentaculata^ in question. 

 The rocks of the district consist entirely of mountain limestone, with 

 the usual veins of iron and copper, and with some traces of old red 

 sandstone. There is a smaller tarn very near, called Little Hazewater, 

 very deep, but containing very few shells. The people in the neigh- 

 bourhood use the shells for strewing on flagged floors, instead of 

 sand; and the deeper layers, which are finely pulverised, are used 

 instead of lime for whitewashing, being a very pure white. A more 

 Extensive deposit of the shell {Bithynia tentaculata^ is to be seen on 

 the Burton and Yealand Mosses, through the centre of which the 

 Milnthorpe turnpike-road passes. The extent of this morass is two or 

 three hundred acres, a great portion of which rests on a thick layer of 

 shells, many of them unbroken, but all without epidermis, and all 

 purely white." 



This, however, is not his own wording, he having borrowed it from 

 the correspondence of a scientific friend of the name of Walling. It 

 would, therefore, be interesting to know who this Mr. Walling was, 

 and if he has written anything on the matter, and we should be glad 



I "The Land and Freshwater Shells of the District around Manchester, 1850." 



