Ixvili INTRODUCTION. 
1. Thus at the Meeting of the British Association (in 1854) it was contended by a 
gentleman of the Government Survey, that the nomenclature was settled, and that I was only 
disturbing a settled point*. One who has put himself in the wrong may well contend for 
this: but I reply, that there can be no settlement which is on a false basis—that no autho- 
rity can vindicate a wrong—that it will not do to perpetuate an error because many may 
in ignorance have embraced it. 
2. By others, the controversy between the author of the “Silurian System” and 
myself was called a mere dispute about words and names. I deny the justice of such an 
assertion. A name, like Cambrian or Silurian, implies a true classification, or the name is 
good for nothing. A true classification implies the application of true principles and the 
right use of them. A name may become the mere watchword of a party, and do infinite 
mischief to scientific truth. Geology is an expanding science; and if its nomenclature 
remain fixed and be not adapted to the advance of facts, it either does not move at all, or 
it moves in fetters. Whenever a great step is taken in physical science and is defined by 
a general name, such as “Silurian System,” that name will assuredly be abused by those 
who have a prurient and incautious appetency for generalizations; nor is it an easy matter 
even for cautious men to escape this kind of mischief. I may quote one or two exam- 
ples that are in point. 
An erroneous identification of a single group in North Devon with the Caradoc Sand- 
stone, imposed on me a task which detained me in Devonshire and Cornwall for the greater 
part of two summers. An erroneous identification of certain Belgian with certain Silurian 
groups, had been made before the Belgian and Rhenish provinces were visited by Murchison 
and myself in 1839. By prematurely accepting some of these identifications we lost the 
labours of nearly half the summer; and though we did make some true steps in advance, 
our joint Memoir was afterwards damaged by our attempt to Silurianize the lower Devo- 
nian groups on the borders of the Rhine. A premature extension of the Silurian groups 
and names over Cambria led the Government Survey into their error in the determination 
of a “Middle Silurian” group. And lastly, the name “Silurian,” which professed to be 
geographical, and based on an accepted physical principle, is to remain fixed at the cost 
of geography, and by the abandonment of the very principles which gave truth and meaning 
to the name. I contend, therefore, that a dispute about names, involves, in the present 
case, nothing more or less than a dispute about the first principles of Science, which we 
cannot violate without damage to the cause of truth. 
3. Thirdly, it was hinted that the classification of the Tabular View virtually embodied 
all new discoveries. If the remark meant anything, it must, at the time it was made, 
have meant that my work was not original, and that I was claiming what was not my own. 
Whatever may have been the value of my work among the older Palsozoic rocks—how- 
J 
* The same fallacy appears more than once in the pages of Siluria. “The point in dispute is settled :” but the 
following questions cannot be suppressed. If the point be settled; by whom? and by what arguments? 
