198 The American Geologist. April, is9o 
in the opinion of the geological party to which he was 
attached, belong to the true drift, they had proposed for them 
the name of the Lawrentian deposits, and he hoped the term 
would be accepted by geologists generally.' 
Prof. H, D. Rogers was present and commented upon these 
clays and sands as he had seen them on the St. Lawrence and 
in New England and said, "The name offered by Mr. Desor he 
was very ready to receive as applicable to a local deposit ;" 
and he says in the "Geology of Pennsylvania," 1858, vol. ii, 
p. 775, "This marine Pleistocene formation has been appro- 
priately named by professor E. Desor the Lawrentian clay." 
In the communication of Desor to the Geological Society of 
France, quoted by Mr. James, p. 31 of the Geologist, he says, 
"As the deposits of this kind are most developed in the valleys 
of the littoral Atlantic, and particularly in the valley of the 
St. Lawrence and of its affluents, I have proposed to designate 
it under the name of Laurentian terrane to distinguish it 
from deposits containing fresh water fossils." W. E. Logan 
in his Report of Progress of the Canadian survey for 1850-51, 
under date of Aug. 20, 1851 (p. 8), speaks of this same marine 
deposit to which ''Mr. Desor * * * * is disposed to give 
the name of Lawrencian." 
These quotations indicate that Mr. Desor intended to name 
this terrane after the valley of the St. Lawrence river. The 
question arises, what is the adjective derived from it? The 
English form is Lawrencian., while the French is Lauren- 
tian. There should therefore be no controversy as to which 
of these modes of spelling is the correct one. H. D. Rogers, 
\y. E. Logan, Z. Thompson, J. W. Dawson, and others, as well 
as Desor himself in his original proposal, use the English form. 
It is therefore improper to chide the reporter of the sub-com- 
mittee upon the Quaternary for quoting Desor as the author of 
the term Lawrencian. 
It does not concern us now whether it was judicious for 
Logan to suggest the name of the same sound for the funda- 
^ It will be noticed that Desor's spelling is neither Laurentian nor 
Lawrencian, but Lawrentian, and Rogers spells it the same way. 
But Logan, Thompson and Dawson, his contemporaries, living on the 
terrane, understood the word correctly. The letter w decides the 
original intent to have been to use the English word, since this letter 
is not used in the French language ; while the t and c are commonly 
interchangeable. 
