Localities of Fossil Shells described hj Mr. Sowerly. 211 



the Dutch gold-leaves within it ; but the excited tube being 

 held under the bottom of the flask, without touchuig it, the 

 leaves diverged, and continued electrified for eight days- 

 Lynn, Aug. 4, 1815. Ez. Walker. 



XXXIX. An alpliuleiical Arrangement of the Places from 

 ivhence Fossil Shells have been obtained by Mr. James 

 SowERBY, and drawn and described tn vol. i. of his '' Mi- 

 neral ConchMy;" with the geographical and stratigraphi- 

 cal Situations ^of those Places, and a List of i heir several 

 Fossil Shells, &c. By Mr. John Farey, Se7i. Mineral 

 Surveyor. 



To Mr. Tilloch. 



Sir,— In page 274, of your last volume, the attention of your 

 Readers was called to the subject of Fossil Shells; since then, 

 three events of considerable importance to the progress ot British 

 Geologv have occurred, viz. the publication of Mr. William 

 Smith's very long expected Map of the Strata, with a short 

 Memoir explaining the same, the completion of Mr. Aaron Ar- 

 rovvsmith's very large and minute Map of England a?id Wales, 

 (by which the localities of Places* can now, in so superior a de- 

 gree be ascertained, which is of the first importance to geological 

 observations), and the completion of vol. i. of Mr. James Sower- 

 bv's " Mineral Conchologzj," with an Index to the 57 genera, 

 and 212 species f of fossil Shells, described therein. 



1 have availed mvself without delay, of the facilities thus af- 

 forded me, to draw up an arranged List of Mr. Sowerby's Shells, 

 according to the Strata to which they severally belong, and men- 

 tioning tlie Place or places where each shell is found ; which ar- 

 rangement he intends to print, as a supplementary Index to his 



first 



* Mr A is now engaged on " An Index to Maps," which is to contain 

 all the Towns, Villages, Houses, Mines, Rivers, Hills, &c. &c. which are 

 mentioned in his great Map of England and Wales, or in any others, or 

 that his Friends may communicate, with their exact hearmgs and distances 

 from known Towns: a work greatly wanted. 



t I think it far more than prohal.le, that repeated and more minute re- 

 search and examination, will extend tiio species of fossil Shells described, 

 or partly so, in this volume, to the number of 244; because in 21 instances 

 the localififs mentioned, are found to belong to two different, and mostly to 

 vervdisti»nl8trat;i,intheseries,anfl in Collier instances, to three such strata; 

 and it is remarkable, that, without being aware of these circumstances, 

 Mr Sowerby has, in far the greater number of these instances, mentioned 

 strikiii" dilfercnces in the Shells, so, for the present, referred by him to 

 the same Species, although, as it now seems, belonging to different Strata. 

 The Species, which I conceive will require dividing, are as follows; riz. 

 •^ Q 2 Ammonites 



