318 Notices respecting Neiv Books. 



Although there seems to be no unconformity in Wales about 

 this horizon, yet in some countries there is a marked change in the 

 lithology ; and here we would again refer to Prof. Schmidt. Had 

 the Lower Palaeozoics been first studied on the southern shores of 

 the G-ulf of Finland there would have been less difficulty in arriving 

 at a definite classification before the personal element had produced 

 any bias on the subject. Moderate in thickness, regular in deposi- 

 tion, devoid of the convolutions and dislocations inseparable from 

 mountain-chains, these ancient and in many places highly f os- 

 siferous beds have been quietly raised so as to form the southern 

 wing of a gently sloping anticlinal. We have already seen that, in 

 this region, the beds containing the second and third faunas (practi- 

 cally those above the base of the Arenig) consist of limestones and 

 marls with insignificant layers of sandstone. Below this line the 

 beds are entirely formed of sandstone, clay, and shale ; they contain 

 fossils, but no Primordial Trilobites of the Paradoxides or Olenus 

 group : hence their identification with the first fauna is not so 

 certain. In whatever way they may be correlated ultimately, the 

 beds in the Baltic Provinces exhibit an important physical change 

 somewhere about the base-line of the equivalents of the Arenig. 



Turning now to Bohemia, we find a very important break about 

 this horizon, " as shown by the absence of the Olenus fauna, and 

 the occurrence of a conglomerate resting unconformably upon the 

 Paradoxides-be&rmg beds * (p. 115). Mr. Marr would no doubt say 

 that, judged by the Welsh standard, this break was below the Trema- 

 doc horizon rather than above it, simply because beds with an admix- 

 ture of ' primordial ' and ' second ' forms succeed in the Bohemian 

 area. Such a point is of minor importance : the main fact to 

 be learned both in Bohemia and on the shores of the Gulf of Fin- 

 land is, that in the one case a marked unconformity, in the other 

 an entire lithological change occurs in the very heart of his hero's 

 Cambran, and that, too, not so very far from the line where the 

 great influx of new forms, alluded to by Mr. Etheridge, occurs in 

 the We^h area. 



In conclusion, we may remark that, apart from all personal ques- 

 tions, there really do seem good grounds for accepting the ideas 

 of Schmidt and Barrande as to the systematic unity of the 

 Palaeozoic rocks below the Old Eed Sandstone. It is one system 

 w^th three large divisions, and the lines which mark off these 

 divisions will be magnified or minimized according to the school to 

 which a given writer may happen to belong. Provided that no 

 names are used, we can allude to the first, second, and third faunas 

 of the Lower Palaeozoic rocks with comparative safety ; but once 

 let a name be used, and the dogs in the opposite camps begin to 

 bark immediately. This arises from a not unnatural desire to have 

 a share of the bone ; and it does seem unjust that the biggest dog 

 of all should be allowed to walk off with the whole of it. But, 

 after all, this question of names is a barren and profitless logomachy 

 which ought not to be allowed to obscure the real issue. Altering 

 somewhat the terms of Prof. Lap worth's conclusion, let us say 



