356 



ON GEOLOGICAL N01IENCLA.TT7EE. 



familiar Pliocene and Meiocene which are terms of less value than 

 those used by Prof. Eenevier in this column : they are both included 

 in the period " Molassique." The Eocene shades off so through 

 the Oligocene into [the Meiocene that it is impossible to draw hard 

 lines between them, and therefore the grouping of this column may 

 perhaps not be approved entirely. The next point in column No. 2 

 that we have to notice is the erection of the Lias into a period of 

 the same rank as the Jui-assic, and of a higher value than the 

 Ehaetic which is included in it. This is a great improvement on 

 some classifications. Even in that of Prof. Morris and R. Jones* 

 we notice that the Rha^tic is made equivalent to the Lias : this 

 seems to us very unfortunate, as in England these beds are not one 

 tenth the thickness of the Lias, and are, paloeontologically, mere 

 passage beds between the Keupcr and Lias — they may be placed 

 under either of them, but are certainly equivalent to neither. 



Below, in the column, we come to a period termed ** Carbonique '^ 

 which includes the Permian, Carboniferoas, and Devonian : we are 

 more accustomed here to the use of "Upper Paloeozoic," — a grouping 

 which English authors will probably continue to use, though it does 

 not follow that Carbonic is too like Carboniferous, or apt to promote 

 misconception. One might even, perhaps, coin a word from some 

 of the more common fossils of the period, such as Sigillaria^ 

 Lepidodendron or Producta, Perhaps more will be inclined to make 

 objection to the period below, which is termed *' Silurique :" we 

 should almost like to restrict this word to the rank given it by 

 Sedgwick or Lyell and other English authors who make it 

 equivalent to, instead of including Cambrian. We shall prefer to 

 use Lower Paloeozoic to include this and the Laurentian, or as an 

 equivalent to the professor's term, we might coin the word 

 " Graptolitien " from a frequent fossil. 



In glancing at the main groups of the first two columns we have 

 deviated from the order of Prof. Eenevier' s explanation of the table, 

 but for the remaining remarks we will read the table horizontally 

 and so follow his text. 



* Synopsis of Lectures on Geology, 1870 (Van Voorst), by Professors 

 Morris and T. Kupert Jones. 



