Quarterly Journal of Conchology. 23 



predominate more in the north-east corner of the county of Durham, 

 say between Shiekis and Hartlepool, having Sunderland for its centre, 

 and some of the romantic valleys which lie between the two extremes, 

 such as Castle Eden Dene, Hawthorn Dene, Hettou Dean, and Eyhope 

 Dean, are very favourite resorts for Conchologists and botanists, and 

 abound with many of the rarer species. Owing to the small extent of 

 marshes and ditches, as also to the absence of canals or sluggish rivers, 

 in addition to the lower temperature, the freshwater species arc much 

 less abundant than in the south of England. Nearly all the rivers, 

 with but slight exceptions, are rapid in their course, over either stony 

 or rocky beds, partaking more of the character of the Scotch rivers. 

 Such may be said to be the character of the river Reed, in the north- 

 west of Northumberland, where very fine specimens of the Unto 

 Margaritifera are to be met with above Otterburn, in the earlier and 

 more precipitous part of its course. 



Sphgerium corneum Linne. — In ponds and ditches ; common 

 throughout the country. 



Sphaerium lacustre Muller. — In ponds ; by no means common 

 throughout the district. It occurs in a pond at Kenton, near New- 

 castle, likewise a pond on the Town Moor, the Keel Quarry pond, near 

 Benton, and a pond near Marsden, county of Durham. This may 

 possibly be the Tellina lacustris of Muller, but as Continental authors 

 consider it distinct, Draparnaud's name has been adopted. 



Pisidium amnicum Muller. — Rather rare ; in slow streams. 

 Occurs near Stockton-on-Tees and the Mill Race in Jesmond 

 Dean. 



Pisidium fontinale var pulchella Jen//ns. — In ponds and ditches ; 

 tolerably plentiful throughout the district. Occurs at Keel Quarry 

 pond, near Benton, 



Pisidium fontinale var cinerea Alder. — Plentiful in a pond near 

 Castle Eden Dean, near Hartlepool; also at Whitley reservoir, near 

 Cullercoats. A more ventricose variety is found in ditches near to 

 Brandling village. 



Pisidium pusillum Gmelin. — In ponds and ditches ; frequent 

 throughout the district. 



Pisidium pusillum ^ar obtusalis Pfeiffer.—OccwLH in some ponds 

 near Darlington. 



Pisidium nitidum Jenyns. — This likewise occurs in some ponds 

 near to Darlington. 



Unio margaritifer Linne. — In mountain streams and rivers in the 

 early and more precipitous part of their course. Very fine specimens 

 occur in the river Reed, above Otterburn, in Northumberland. 



Anodonta cygnea Linne. — In ponds, only occasionally. Occurs 

 in the Black Pool, near Dinningtou, Northumberland. 



Neritina fluviatilis Linne. — This has been frequently met Avith on 

 our coast, but as it is a common ballast shell, must be attributed to 



