XV. 



HISTORY OF THE NAMES CAMBRIAN 

 AND SILURIAN IN GEOLOGY. 



The present essay appeared in the Canadian Naturalist for April and July, 1872, and 

 the first two parts of it were reprinted in Nature for May of the same year, and sub- 

 sequently in the Geological Magazine in 1873, while a French translation of the entire 

 paper by Dewalque, with notes and additions, is announced as about to appear in 

 Belgium. 



Having been desired, in 1872, to prepare for publication a notice of the scientific 

 labors of Murchison, it became necessary for me to examine critically the whole ground 

 of the Cambrian and Silurian controversy, a task which proved much more serious than 

 I had supposed, and brought to light facts which both surprised and pained me. In 

 the interest of truth I determined to write the history as I have here given it, and 

 I had the great pleasure of laying this statement, in its completed form, before the 

 venerable Sedgwick, who, in several letters written to me during the last months of 

 his life, testified his gratitude for the manner in which justice had at length been 

 done to him and to his labors, and, moreover, warmly acknowledged it in the Preface 

 to a new Catalogue of the Cambridge Fossils, dictated by him a few months before 

 his death, which took place in his eighty-eighth year, at Trinity College, Cambridge, 

 January 27, 1873. That Preface contains a more circumstantial and complete account 

 of the personal history of the controversy than had previously appeared. 



Such a history as this of the Cambrian and Silurian rocks of the Old World was not 

 complete without an account of the progress of our knowledge regarding the similar 

 rocks of North America ; and I have, therefore, in the third part, endeavored to set 

 forth in an impartial manner the share of each investigator in the working out of this 

 important chapter in the geological history of our continent. I have, in the present 

 reprint, made several important additions, and some changes with the view of ren- 

 dering more complete, both for Great Britain and North America, the history of these 

 older palaeozoic rocks. The additions and the important changes, whether in notes 

 or in the text, are distinguished by being enclosed in brackets. 



IT is proposed in the following pages to give a concise ac- 

 count of the progress of investigation of the lower palaeozoic 

 rocks during the last forty years. The subject may naturally 

 be divided into three parts : 1. The history of Silurian and 

 Upper Cambrian in Great Britain from 1831 to 1854; 2. 

 That of the still more ancient palaeozoic rocks in Scandinavia, 

 Bohemia, and Great Britain up to the present time, including 

 the recognition by Barrande of the so-called primordial palaeo- 



