C. Lapicorth — Classification of the Lower Palaeozoic Rocks. 3 



light of Murchison to all the strata between the base of the Arenig 

 and the summit of the Ludlow, but emphatically assign the Lingula 

 Flags and Paradoxicles Beds to the Cambrian. This school — if 

 school it maybe called — has been greatly aided by the wide publicity 

 given to their views in the numerous memoirs in which they record 

 their steady and cautious advance in working out the natural 

 succession among the subordinate members of the Lower Palaeozoic 

 Eocks. It is just possible that, owing to the modesty of the claims 

 it makes for Sedgwick, and to its retention of such a large proportion 

 of the prevalent nomenclature, this view might gradually and 

 insensibly have taken possession of much of the field, were it not for 

 the persistent exertions of the Cambridge School, smarting under a 

 sense of injustice, and determined to rest satisfied with nothing less 

 than a complete redress of those historic grievances, which their 

 affection for the honoured name of Sedgwick has led them to regard 

 as little less than personal to themselves. 



But the partial success that has already attended the earnest con- 

 scientiousness and perseverance of the members of the Sedgwickian 

 party has, in truth, hastened the evil day. The result that their 

 efforts have had in calling the attention of geologists to the salient 

 points of the question at issue, is as fatal in its effects upon their 

 own theory, as it is upon that of their opponents. By their recent 

 adoption of the Lyell-Hicks line of demarcation at the base of the 

 Lower Llandovery, they furnish, indeed, a thorough demonstration of 

 the almost perfect palasontological distinctness of the faunas of the 

 so-called Lower Silurian formations, and those of the true or Upper 

 Silurian, and the consequent impossibility of combining them philo- 

 sophically in one and the same system. But, in spite of all that is 

 implied to the contrary, this course is, in effect, a distinct abandon- 

 ment of Sedgwick's fundamental argument that these systems were 

 necessarily distinct, from the fact that in the typical areas their beds 

 were stratigraphically discordant. It amounts, on the other hand, 

 to an implicit adoption of the only safe principle, that we have no 

 reliable chronological scale in geology but such as is afforded by the 

 relative magnitude of zoological change — in other words, that the 

 geological duration and importance of any system is in strict pro- 

 portion to the comparative magnitude and distinctness of its collective 

 fauna. It appears to me that it is impossible for them to rest here, 

 but that their next and inevitable step will be the further admission 

 that the Lyell-Hicks division of Cambrian and Loioer Silurian are as 

 rightly entitled to the rank of separate systems as the true or Upper 

 Silurian itself; and that, eventually, their rigid sense of fairness 

 and justice will lead them so to discriminate them. 



For, amid all the confusion incident to this controversy, one grand 

 fact stands out clear and patent to the most superficial student of 

 Palaeozoic geology — namely : — the strata included between the 

 horizon marking the advent of Paradoxicles, and the provisional 

 line presently drawn at the summit of the Ludlow, imbed three 

 distinct faunas, as broadly marked in their characteristic features as 

 any of those typical of the accepted systems of a later age. 



