8 C. Lcqnvorth — Classification of the Lower Palceozoic Hocks. 



the Silurian System as far as a Trilobite lias yet been detected, sinking 

 it deeper and deeper into the earth as the progress of discovery 

 reveals the evidence of the former presence of organisms in strata of 

 yet older and older date, at the same time extending its highest 

 boundary upwards into the supra-Ludlow formations as we detect . 

 the presence of an occasional fossil of a Ludlow type yet higher and 

 higher in the more rapidly accumulated Eed Sandstones above the 

 Bone beds, till our unwieldy system includes half the fossiliferous 

 sediments of the globe, and its very subdivisions are almost equal in 

 classificatory importance to the accepted systems of a later date ? 



Or shall we adopt the methods of the traditional followers of 

 Sedgwick, and, drawing a rigid line of demarcation at the base of 

 the Lower Llandovery, imitate our opponents to the extent of erecting 

 all the anterior fossiliferous strata into a gigantic system, on the 

 ground that they were so combined by its founder, and in the delusive 

 hope that we shall find at its base a universal unconformability, so 

 that the name Pre- Cambrian will ever remain a synonym of the 

 metamorphic and possibly azoic formations ? 



Or, with Lyell, shall we condone the past, and give a double share 

 to the stronger party ; consoling ourselves with the reflection that, 

 after all, the question is merely a question of names, and not of 

 principle; arguing that the injustice we tolerate did not originate 

 with us, and is less the crime of a party than the inevitable result 

 of untoward circumstance ; and justifying our procedure in the eyes 

 of the world by the implication that the general adoption of the 

 larger portion of the Murchisonian nomenclature is already an ac- 

 complished fact, upon which it would be ridiculous to expect that 

 any feeble efforts of ours would ever have the slightest influence ? 



Or, ought we rather to cast in our lot with the few who employ 

 the term Cambro- Silurian or Siluro- Cambrian for the rocks of 

 the Second Fauna, and try once again the oft-repeated and as oft- 

 defeated experiment of reconciling the claims of both parties by 

 allying the strata in dispute to two systems at once, in the use 

 of titles which their very founders themselves abandoned as incon- 

 venient and absurd ? 



Or, finally, standing aloof from all parties, shall we, in the name 

 of science, claim the right of fully recognizing the systematic 

 equality of the three Lower Palaeozoic Faunas, by regarding the 

 three successive rock-groups which contain them as individually 

 entitled to the rank and denomination of a complete system ? 



It seems to me that to every unprejudiced mind it will be 

 apparent that the adoption of this last course has now become an 

 absolute necessity. Geologic truth and convenience imperatively 

 demand a separate place and name for each of these systems. It 

 only remains for us so to arrange their titles that no real injustice 

 shall be committed. 



Dr. Hicks's definition of the Cambrian system as including the 

 Paradoxides- and Olenus-bearing beds, from the base of the Harlech 

 Grits to the summit of the Lower Tremadoc is by far the best that 

 has hitherto been proposed. Thus restricted, the title is synonymous 



