246 J. E. Marr — Cambrian and Silurian Rochs. 



Murchison himself, and in the paper under consideration he supports 

 this classification. 



It may seem presumptuous to question the adoption of this 

 classification by the great expositor of the Bohemian basin, but I 

 Avould submit that it is not sufficient to judge of the merits or 

 demerits of an historical classification, from its application to an 

 isolated area, apart from the classical one, but it should be ascer- 

 tained whether it can be applied over much larger tracts of country. 



M. Barrande first expresses a regret tliat Murchison and Sedgwick 

 studied only stratigraphical geology, and neglected palaeontology, 

 and attributes to this cause the confusion which has arisen. But not 

 only had these two geologists considerable knowledge of paleeon- 

 tology themselves, but they also employed palgeontologists of the 

 first rank to assist them in their labours. Moreover, so far from 

 the confusion having arisen from palgeontological errors, it arose 

 from mistakes in stratigraphy, in which the Woodwardian Professor 

 had no part ; it would be presumption on my part to enter further 

 into this personal question, after the masterly essays of Sedgwick 

 in the prefaces to " British Paleozoic Rocks and Fossils," and " A 

 Catalogue of Cambrian and Silurian Fossils," and the able defence 

 of Sterry Hunt, reprinted in his " Chemical and Geological Essays." 



M. Barrande then goes on to state that the three faunas which he 

 names primordial, second, and third, can be traced over very wide 

 areas, whereas the smaller subdivisions (Stages) have no exact 

 parallelism in different countries. This is to a certain extent true of 

 deposits formed in shallow water, but the black muds which indicate 

 deep-water conditions are very widely spread. I may cite as an 

 instance of this the occurrence of the Arenig fauna in countries as 

 widely separated as Britain, Sweden, Bohemia, France, and Spain. 



The characteristics given of the three faunas admit of so many 

 exceptions, as to be of very doubtful classificatory value. The 

 primordial fauna is said to be composed almost entirely of Trilobites : 

 this may be the case where the deposits are of a deep-sea character ; 

 but whenever indications of shallow water occur, Brachiopods 

 abound, e.g. in the Lingula Flags of Britain, the Olenus beds of 

 Scandinavia, where OrtJns is very abundant in the calcareous beds,^ 

 and in a paper read before the Geological Society, June 9th, 1880, I 

 gave reasons for supposing certain grits of Bohemia, crowded with 

 Lingula Feistmanteli, to be the equivalents of the Lingula Flags of 

 Britain. 



"In the second place these primordial Trilobites are characterized 

 by their conformation," the head is small, the thorax large, and the 

 tail scanty (exigii) ; this scantiness is explained as not referring to 

 the extent of the tail, but to the small number of segments of which 

 it is composed. In reply to this I may remark that the tails of such 

 genera of the second and third faunas as Bemopleurides, Acidaspis, 

 and various genera of the Cheiruridce are strictly comparable to those 

 of Paradoxides, etc., of the primordial fauna. 



^ Cf. Linnarsson, Biliang till K. SvenskaVet. Akad. Handl. Eand 3, No. 12. 



