26 Mr. Alder's Catalogue of Land and Fresh-water Shells. 



No. VI. — A Catalogue oj" the Land and Fresh-water Testaceous Mol- 

 LuscA found in the Vicinity of Newcastle upon Tyne, with Remarks. 

 By Mr. Joshua Alber. 



Read March 16, 1830. 



J. HE following Catalogue of a humble and inconspicuous, though not 

 uninteresting, portion of our native animals, is now offered to this So- 

 ciety as a small contribution towards a Provincial Fauna. It will serve 

 to shew a part of what has already been done towards ascertaining our 

 indigenous Mollusca, and may be useful to the future inquirer by point- 

 ing out the habitats of many of the rarer species. It is hoped also that 

 it may be the means of eliciting some further information on the sub- 

 ject ; for the present list, drawn up principally from observations made 

 in occasional rambles into the country during leisure hours, for the last 

 three or four years, cannot be presumed to be complete. 



Besides their local uses. Catalogues like the present, if founded upon 

 a careful investigation of nature, will usually be found to record some 

 new facts interesting to the general naturalist ; some species perhaps 

 not before observed, or some peculiarity in the habits and economy of 

 those already known. They will, at the same time, always afford in- 

 formation with regard to the geographical distribution of the species, 

 a branch of Natural History which has lately engaged particular atten- 

 tion, but which is as yet very imperfectly understood. 



In tracing the distribution of the land and fresh-water Mollusca in 

 this neighbourhood, we shall find them influenced, in some degree, by 

 the geological features of the country. The greatest part of the dis- 

 trict in which the following observations have been made, is composed 

 of the series of strata usually called the Coal formation, joined, towards 

 the south-east, by the Magnesian Limestone. The whole of this district 



