224 WHITMAN CROSS 
now wish to touch upon the cited rules or actual practice of the 
government Survey, since the question of revising those rules is, 
at the time of writing, under consideration by a committee 
appointed by the Director. There is ample room, however, for 
a discussion of ‘the natural objects of a geological map and an 
analysis of the actual conditions facing the geologist endeavor- 
ing to express geologic facts upona map. The writer aims to 
do this in no controversial spirit, making frequent reference to 
the articles cited simply because they are the latest expressions 
of a view held by many geologists. 
Before entering into the discussion of the geological prob- 
lem, the writer wishes to express a protest against a tendency of 
the time to impoverish the language of ordinary speech by the 
appropriation of many of its commonest terms, having univer- 
sally adopted and understood meanings, to technical and spe- 
cific purposes. This is found in other languages than our own, 
and in the literature of other sciences than geology, but for both 
general and specific reasons some of the terms necessarily 
employed in this discussion may be mentioned as cases in point. 
When such terms)asi ““ieroup,, (division, Seniesa peniodin 
and ‘‘formation’’ are appropriated for special and limited uses 
the geologist is decidedly hampered in his general discussions 
and obliged either to employ unusual terms for common con- 
cepts, or to carefully and repeatedly explain his use of terms as 
he goes along. That restricted definitions of some of the terms 
mentioned have the sanction of the International Congress of 
Geologists merely makes the situation worse. The importance 
of this matter appears not to be limited to the indirectness of 
statement forced upon a writer in discussing the commonest 
points of geology and to the inconvenience of so doing, for 
unless a writer does explain his use of terms there is often 
uncertainty as to his meaning, and the unnatural limitation 
imposed may well act at times as an obstacle to clear thinking. 
It seems desirable to refer to this matter because the uses of 
the word “formation” and of the expression ‘“ lithologic indi- 
vidual” or ‘“‘unit’’ by Messrs. Willis and Eckel, in their cited 
