LIMITATIONS OF PRE-CAMBRIAN NOMENCLATURE 333 
geological history of the various parts of this territory in pre- 
Cambrian time would be the same; that the geological succession 
of formations so far determined to be present in these various 
parts indicates that their history has not been the same; that the 
pre-Cambrian formations occurring in the St. Lawrence basin fall 
naturally into a number of separate subprovinces; and that it is 
advisable for the present that a separate nomenclature be employed 
in each of these subprovinces. 
The principal advantages that might be attributed to the 
widespread correlations implied in the present nomenclature applied 
to the pre-Cambrian rocks of the St. Lawrence basin are that they 
serve as tentative hypotheses for the investigator in the field, and 
as summaries of existing knowledge for the science as a whole. 
But it is doubtful whether tentative hypotheses have a place in 
geological nomenclature, and furthermore, for the investigator 
familiar with the facts in the field, tentative correlation tables 
indicating the most probable relationships of the formations 
occurring in the various subprovinces can afford all the advantages 
of a regional nomenclature, and for those’ not familiar with the 
facts in the field a general classification from which names of local 
origin are excluded could be used. Such a classification might 
be less definite, but it would be scientific, since it would express 
what is actually known, or what is at least generally accepted, by 
those familiar with the facts in the field rather than tentative 
hypotheses. 
