216 Retrospective Criticism, 



Gray^s Natural Arrangement of British Plants. — You have not inserted 

 the query I sent you on this book. [We sent it to an eminent botanist, 

 whose answer we did not think it advisable to insert ; but we now regret 

 not having done so.] The expression in SmitWs Flora is, " I have also, for 

 the first time in a general British Flora, introduced the natural orders of 

 our plants ;" which is, supposing he knew of Gray's work, a palpable 

 falsehood. I have heard the increased number of terms, and the multipli- 

 cation of genera, in Gray, objected to ; but is not this the consequence of 

 the progress of science towards perfection ? If organs are really different 

 in form, although intended for similar purposes, such as seed-vessels, surely 

 it is better to designate such organs by a particular term, which at once 

 conveys to the student the idea of the form and construction of the part 

 in question. But some of your readers will favour me with an opinion 

 on the subject ; because the work, if it has any merit, ought not to be cast 

 into oblivion, merely because this or that author, however high he may 

 stand, chooses to pass it over in silence. It has one advantage over all 

 other works of the kind, in the English names being generally a transla- 

 tion of the Latin names ; and if the derivations of the generic names 

 had been given, it would have been, in this respect, complete. — 1). S. 

 July 28. 1828. 



Geological Arrangement of British Fossil Shells. — Sir, In the Table of 

 the Geological Arrangement of British Fossil Shells, which you did me the 

 favour to insert (p. 26.), an accidental transposition of a line, in the press, 

 has occasioned an error it may be useful to correct. At p. 34., the genus 

 Solen should commence with the upper green sand, which formation, by the 

 inadvertent transposition alluded to, is placed two lines above, under the 

 genus Saxicava. It becomes the more desirable to point out this circum- 

 stance, because it is the first time, I believe, that the occurrence of Solen 

 in any but the tertiary beds has been noticed. 



At present only one species of Solen, S. afFinis of the London clay, seems 

 to have been noticed in our treatises on mineral conchology. It is probable 

 that there are several other species, and I believe I am correct in mention- 

 ing their occurrence in the following beds : — 



In the Green sand below the chalk 1 species. 

 London Clay - - 2 



Crag - - 3 



Whether there be a repetition of species in any of these formations is un- 

 determined. 



It need scarcely be remarked here, that the Table of Shells is susceptible 

 of considerable extension, as almost every collector possesses a few unde- 

 scribed specimens. It is sufficient, for the present, that a// the character- 

 istic fossils are included therein ; and, however extensive the subsequent 

 additions, it is not very probable that the relative proportions of their num- 

 bers, in the different geological eras, will eventually be found to vary much 

 from the estimates which the present state of science enables us to form. 

 At some future period, perhaps, I may trouble you with an amended Table ; 

 .and I mention this with the hope that the pages of your Magazine may be 

 ;One medium of adding to our knowledge of these interesting remains of a 

 .former world. I shall consider myself honoured by the notice, either by 

 this means, or privately, of any authentic species and localities of unde- 

 - scribed fossil Testacea. — B. C. Taylor. 7. Wilmington Square, London, 

 Aprils, 1829. 



