728 Mr. Lonsdale on the Age of the 



necessarily very incomplete. It has been compiled in part from Mr. Hennah's 

 valuable collection, with the assistance of Mr. James Sowerby ; and it is 

 impossible to allude to that collection without speaking in terms of the warmest 

 admiration of the liberality of spirit, which placed the whole series at the 

 command of Prof. Sedgwick and Mr. Murchison ; and of the zeal and assi- 

 duity with which the smallest specimens have been collected and preserved. 

 I have also been permitted to use a valuable manuscript list drawn up by 

 Mr. Austen, in part from specimens named by M. de Verneuil ; and I have 

 taken advantage of the information contained in the published lists of Mr. De 

 la Beche and Mr. Phillips. I may be permitted to add, that I have compared, 

 as far as I have been able, the species mentioned in those documents with 

 accessible specimens, particularly a portion of Mr. Austen's valuable collec- 

 tion, and another kindly lent me by Mr. Daniel Sharpe. 



The list contains 62 species, 10 of which have been assigned to carboni- 

 ferous fossils, and 13 to Silurian ; and the remaining 39 have not, it is believed, 

 been found in England except in the limestones and associated beds of South 

 Devonshire. In the list is not noticed a large number of fossils still un- 

 named, including many species in Mr. Hennah's and Mr. Austen's col- 

 lections. 



The ten species considered to agree with mountain-limestone fossils, do 

 not include one decided coral common to the carboniferous and Devonshire 

 limestones. The shells are Terehratula Jlexistria* , T. acuminata, T. pug- 

 nus, T. Mantia*, Spirifera (Trigonotreta) ohlata*, S. subconica ? Pecten 

 plicatus, Pileopsis vetustus ? Buccinum imhricatum, and B. acutum*. The 

 four species marked with an asterisk I have not seen, but they are included 

 on the authority of Mr. Austen's and Mr. Phillips's lists. The Cyrtia and 

 Pileopsis are also not positively identified. 



The whole of the nine species occur in that lower portion of the carbo- 

 niferous limestone series, to which the term carboniferous or mountain-lime- 

 stone has been particularly applied ; but it is a subject of regret, that we have 

 not more precise data respecting the distribution of organic remains in that 

 formation, which not unfrequently equals in thickness the oolitic series of 

 Wiltshire ; yet it is well known that the fossils of the upper calcareous divi- 

 sions of that oolitic series differ considerably from those in the lower. 



On the fossils considered peculiar to the Devonshire limestone it is not ne- 

 cci^sary to offer any remarks, for the present comparison is confined solely to 

 England. 



Of the thirteen Silurian fossils eight are corals and five are shells. The lat- 

 ter are Terehr alula prisca, T. aspera, T. JVilsoni, Spirifera (Trigonotreta) 



