Secondary Bocks. 115 



ing upon carboniferous strata, throughout more than two- 

 thirds of a basin which has a circumference of not less than 

 4000 English miles ; that is, it occupies a space greater than 

 twice the area of P'rance. 



The palaeozoic series in North America ends with the Car- 

 boniferous rocks ; for although that and the inferior groups 

 are developed on so great a scale, a narrow zone of red sand- 

 stone on the Atlantic slope, celebrated for containing the 

 footmarks of giant birds, which, in the opinion of Professor 

 Rogers, belongs to the Trias, is almost the only sedimentary 

 deposit between the Carboniferous and the Cretaceous rocks. 



The Secondary Rocks. 



The Trias, so largely developed in other parts of Europe, 

 is unknown in European Russia. 



It is remarkable that, except one member of the oolitic 

 series, the whole of the secondary formations between the 

 Permian and Cretaceous groups should be wanting in Russia ; 

 and that, with the exception of a very limited and even 

 doubtful oolitic deposit in Virginia, not a trace of them 

 should have been found from the Atlantic to the Mississippi, 

 and even as far west from that river as any geologist has yet 

 penetrated. Professor Rogers rests his determination of 

 this deposit in Virginia as belonging to the lower part of the 

 oolitic series, solely on the striking resemblance as a group 

 of certain plants, accompanying a bed of coal which it con- 

 tains, to those which are found associated with the oolite coal 

 of Brora, Whitby, and other European localities. He says 

 that, "judging by lithological indications alone, perhaps no 

 more probable conclusion would have been reached on the 

 subject than that of the able geologists Mr Maclure and Mr 

 R. C. Taylor, the former of whom assigned this deposit, con- 

 sisting of slates and of coarse grits composed of the mate- 

 rials of granite so little worn as to have the aspect of that 

 rock in a decomposing state, and resting upon gneiss, and 

 without any calcareous bed, to the period of the Old Red 

 Sandstone ; the latter to the " transition carboniferous de- 

 posits." If it be true, that, in the Alps, species of plants 

 identical with those of the carboniferous period have been 



