556 Geological Society: Anniversary Address, 1842. 



life as the earliest appearance of Saurians is to be taken as the limit 

 of one vast geological division, we must exclude the magnesian lime- 

 tone from the older series, and Mr. Phillips's proposed extension of 

 the term Palaeozoic cannot be sustained. Adopting this principle of 

 the vertebrata as our guide, we may go on to say, that the true Silu- 

 rian type ceases in the ascending order at that band of rocks which, 

 in truth, forms tlie very uppermost layer or summit of the Silurian 

 strata, in which the lowest order of vertebrata or fishes first appear, 

 and then having ascended through another vast series, loaded with 

 peculiar ichthyolites, we may announce a new aera in the magnesian 

 limestone or zechstein, where we meet in the Saurians with another 

 and higher class of the animal kingdom, wholly unknown in the in- 

 ferior beds. It was, I beg to say, on this principle that I formerly 

 proposed to divide the strata of England into seven great systems, 

 as expressed in the small map of England which accompanies the 

 map of the Silurian region. I do not assert that this general classi- 

 fication of the British geological series should be preferred to that 

 of Mr. Phillips. He may contend that the universally distributed 

 mollusk affords a more useful horizon line than any class of the 

 higher order of animals. I merely state the case, and I hope fairly, 

 to show that whether geographical terms be ultimately adhered to 

 or rejected, all nomenclature founded solely upon our present know- 

 ledge of the distribution of animal and vegetable life, must be 

 liable to change with every new important discovery, whilst that 

 terminology which involves no such hypothesis, but is simply based 

 on the proofs, that within a given region certain groups of beings 

 are included, can never be gainsaid. It is on these grounds, there- 

 fore, that I am encoui-aged to hope, that the word " Silurian," 

 which lias been warmly sanctioned by the classic authority of Von 

 Buch, which E. de Beaumont and Dufrenoy have engraved upon 

 their splendid map of France, and which our fellow-labourers in 

 America have adopted, will not be obliterated to make way for 

 other names which are not founded upon any new distinctions, stra- 

 tigraphical or zoological. So long, gentlemen, as British geologists 

 are appealed to as the men whose works in the field have established 

 a classification, founded on the sequence of the strata and the im- 

 bedded contents, so long may we be sure that their insular names, 

 humble though they may be, will, like those of our distinguished 

 leader William Smith, be honoured with a preference by foreign 

 geologists, who, looking from a neutral ground, are sure to be the 

 most impartial judges. The perpetuity of a name affixed to any 

 group of rocks through his original research, is the highest di- 

 stinction to which any working geologist can aspire. It is in truth 

 his monument, and therefore, gentlemen, I trust you will pardon me 

 if I have occupied you too long with the allusions to this point, 

 and which have been elicited by the work of one for whom I enter- 

 tain so high an esteem as Mr. Phillips. I will therefore only add 

 my hope, that now when the term Silurian has been so widely 

 spread, the Director of the British Geological Ordnance Survey, 

 who encouraged the author of the ' System ' to propose a separate 



