J. W. Judcl — On the use of the term Neocomian. 221 



of such rules of nomouclaturo liavo boon very fully discussed and 

 defined in the Report of a Committee of the IJritish Association, and 

 in several papers by the late Ilu^h E. Strickland. 



In deciding upon a date, which may serve as a limit in suchi 

 retrospective revision as may be called for, geologists will experience 

 little difficulty. William Smith is the Limucus of Strati graphical 

 Geology, and the year 1815, the date of the publication of the " Map 

 of the Strata of England and Wales," may be safely considered as 

 the era of the foundation of our system of geological nomenclature. 

 All earlier names, with possibly one or two exceptions, may, like 

 the Biological terms of Ray or Morton, be safely neglected, and the 

 rival claims of all post-Smithian names will then have to be decided 

 according to the date of their first proposal. This rule will of 

 course have to be relaxed when it can be shown that the earlier 

 term is founded on a mistake, involves a palpable absurdity, or leads 

 to gross misconception. All projects, like that of D'Orbigny, for 

 revolutionizing the terminology of the science, in an attempt at an 

 impossible symmetry, may be safely disregarded; especially when 

 they are based on principles so arbitrary, and methods so Procrustean, 

 as those of the French palasontologist, and lead to results so anoma- 

 lous as making divisions like the Turonien and Callovien, equi- 

 valent to such as the Carboniferien or Silurien. Such terms as 

 "Lias," "Cornbrash," and " Gault," if they have not the same 

 advantages of euphony as the later names '•' Silurian," " Neo- 

 comian," and " Miocene," have even stronger claims from prescrip- 

 tion ; and now that they have become so thoroughly established 

 in the geological literature of Europe, any attempt to supersede 

 them would, be as unjustifiable as it w^ould probably be futile. 

 Of course it is not necessary here to assert the cosmopolitan nature of 

 science, nor to insist upon the equal claims of designations, whether 

 of British or foreign origin. 



The object of the present essay is to examine historically and 

 critically, according to the principles just laid down, the terminology 

 of a certain series of deposits. Some writers, who have done me 

 the honour to notice my papers on the Neocomian strata of the 

 North of England, have unfortunately so far misunderstood my 

 object as to represent me as introducing a new system of nomen- 

 clature. On the contrary, as I now propose to show, the name 

 Lower Greensand had its origin in a series of mistakes and mis- 

 conceptions, while the term Neocomian is that which must be 

 adopted according to the law of priority, and in fact has claims of 

 the same nature and force as those which may be urged in behalf of 

 the term Silurian. 



It seems to be impossible, as Webster has observed, to determine 

 the exact date when the term Greensand first came into use among 

 geologists. As is well known, the observations and even the no- 

 menclature of William Smith had, by his liberal oral communica- 

 tions, become very generally known to geologists long before his 

 friends succeeded in persuading him to publish his first map. In a 

 table of the strata near Bath, drawn up in 1799, Smith calls the bed 



