CEROLOGIG VERS OS ELTHTOLOGTE 229 
years ago, and to that step as much as to the recognition of 
paleontology is due the present science of structural and histori- 
cal geology. Perhaps Mr. Willis did not intend to use the term 
‘“‘rock”’ in its natural and limited sense, yet the proposition to 
‘make a geologic map a representation of ‘‘lithologic individuals” 
discriminated solely on “‘lithologic character” affords no basis 
for the supposition that he had in mind the idea of the geologic 
formation, properly speaking. To advocate such a map is prac- 
tically no advance upon the time of John Macculloch, who in 
1821 published his celebrated Geological Classification of Rocks, 
etc., having stratigraphy in mind, and with no idea of the neces- 
sity for a science of rocks. There is in the idea, however, a 
curious combination of this old-time misconception with an ele- 
ment of the so-called ‘‘new geology,” which is chiefly occupied 
with physical conditions under which the earth is sculptured 
and detrital rocks are formed, although this branch of geology 
is no more mew than any other. 
From the statements by Mr. Willis that he “by no means 
advocates disregard of fossils in the zdentefication of formations ;”’ 
that “there is a difference between using fossils as one of sev- 
eral-means of zdentification and employing them as essential char- 
acters ;”’ and that ‘“‘they should not set limits in the discrimination 
of formations” (2¢a/ics the present writer’s), it appears that there 
is an unrecognized or imperfectly expressed acknowledgment that 
the Jenkinsville sandstone, for example, is more than a sand- 
stone exposed in a ledge at Jenkinsville —that it is, in fact, a geo- 
logic formation. But the writer confesses that he does not fully 
d 
understand the use of the terms ‘‘identify’’ and ‘‘essential’”’ in 
these quotations. Apparently Mr. Willis would discriminate and 
define ‘‘formations”’ by their lithologic characters as the only 
“essential” factors, but still realizes that such formations may 
not be recognizable by their ‘‘essential’’ characters and that the 
accidental or unessential factors, fossils, may then be useful or 
necessary. How and where would Mr. Willis express the facts 
concerning certain fossils in relation to the Jenkinsville sand- 
stone which warranted or made possible their use in zdentifying 
