114 A. W. Jackson — Nomenclature of Crystalline Bocks. 



a name that shall be as little subject to change as possible, for 

 change produces confusion. 



Classifications are constantly changing and if our rock-names 

 are made dependent upon them, an element of confusion in 

 nomenclatu- and unnec- 



essary. Our only remedy lies in a complete divorce of nomen- 

 clature from clarification such as has long been recognized in 

 zoology, botany and mineralogy.* 



In the following pa»es I wish to discuss the principles of 

 nomenclature as considered thus entirely distinct from classifi- 

 cation ; it goes without saving tli;it the chemical, inineralogical. 

 and geologict) 1 considerations which 1 discuss with reference to 

 the irbearing on nomenclature sire entirely open to a re-discussion 

 with reference to their bear ig oi <:[ n <ijicot.lon ; and one may 

 arrive at diametrically opposite conclusions as to their value for 

 classification from my own as to their value for nomenclature 

 without in the least invalidating the results reached in the 



In the first chapter I state and explain the principles which 

 I conceive should guide us in the formation of rock-names and 

 I then examine the considerations at our disposal to <) 

 how far they may be used in conformity with the principles 

 laid down. In the second chapter I explain why I hold it to 

 be inexpedient to formulate a system of names in accordance 

 with the principles suggested and give reasons for adopting 

 provisionally a different system of names. 



Chapter I. 

 I conceive the fundamental principles to be borne constantly 

 in mind in the formation of a system of nomenclature to be 

 three: I. Uniformity, II. Stability, III. Adaptability. I shall 

 examine each of these and indicate its bearing upon the ques- 

 tion at issue. 



I. Uniformity. No one will for a moment dispute the i lesi ni- 

 hility of having but one name for each rock. There is some- 

 thing of a tendency toward the formation of " schools " in this 

 respect. That is all wrong however ; all geologists should call 

 the same rock by the same name. Zoologists, botanists and 

 mineralogists recognize this principle in their respective sci- 

 ences. Indeed it is so evident that one who will dispute it is 

 not to be reasoned with. 



II. Stability. By a "stable " nomenclature, I mean one that 

 is not subject to change. A rock that has once received a defi- 

 nite name should continue to be known by it. This principle 

 is second in importance only to the first. If all geologists 

 would iigree to change any given name, there would of course 



