206 
vicinity of Baltimore, Washington, and to 
some extent in the Smoky Mountains of 
North Carolina. The coordination of the 
observations in the pre-Cambrian rocks is 
entrusted to Professor Van Hise. The re- 
sults will be published in part in coopera- 
tion with the Maryland Survey, in future 
folios of the Geologic Atlas, in the Wash- 
ington folio, for which the manuscript is in 
hand, and in reports and folios relating to 
the Cranberry and Cherokee districts of 
North Carolina. This last-named work is 
performed partly in cooperation with the 
State Geological Survey of North Carolina. 
In the Atlantic Coastal Plain the latest 
contributions to geology have resulted from 
the investigations supported by the State 
Surveys of New Jersey and Maryland. The 
study of the surficial deposits broadened 
the basis of stratigraphic discrimination, 
and the combination of minute observations 
in stratigraphy with elaborate studies of 
paleontology has led to recognition of im- 
portant details in the EKocene and Miocene 
‘sections. Our views of unconformity and 
of the nature of oscillation of the Coastal 
Plain will probably be widened by the pub- 
lication of these results. That, however, 
is not yet an immediate prospect, except in 
so far as they have appeared in the State 
reports of New Jersey and Maryland. 
Surveys of the unaltered Paleozoic strata 
in the folded zone of the Appalachian prov- 
ince are not now being extended. The 
number of quadrangles surveyed and folios 
issued or about to be issued is large. With 
the exception of one folio, the Maynard- 
ville, shortly to appear, the valley and a part 
of the plateau region of eastern Tennessee 
are mapped in published folios, and the 
area of continuous surveys extends into 
Georgia and Alabama on the south and 
into Virginia on the north. Representative 
folios for the valley of northern Virginia 
cover over 6,000 square miles and fully ex- 
hibit the peculiarities of structure. Folios 
SCIENCE. 
[N. S. Von. X. No. 242. 
relating to Paleozoic stratigraphy and Ap- 
palachian structure issued during and since 
1896 are Nos. 27, 28, 82, 33 and 35, or the 
Morristown, Tenn.; Piedmont, Va., Md. 
and W. Va.; Franklin, Va. and W. Va.; 
Briceville, Tenn., and Gadsden, Ala., re- 
spectively. 
The accuracy of the work performed by 
geologists who preceded the United States 
Survey in the Appalachian coal fields, and 
the importance of the economic interests in- 
volved, led to the use of the most careful 
stratigraphic and structural methods in that 
field. Unwilling to trust to correiation of 
lithologically similar strata which have not 
been mapped continuously, the geologists 
have measured and named local sections on 
the assumption that they may not be able 
to correlate the individual beds in each. 
The position of any stratum is determined 
throughouta network of intersecting sections 
which are checked against the bench marks 
established by precise level lines in course 
of the topographic survey. Lithologic 
variations are carefully noted from area to 
area, and each distinctive lithologic unit is 
identified so far as it is actually traceable, 
but correlation is not continued beyond 
that point. The stratigraphers have been 
greatly aided by the appreciative coopera- 
tion of the paleobotanist, and the result will 
be to establish our knowledge of the stra- 
tigraphy of the Coal Measure formations 
upon a sound basis of fact. The tendency 
of the observations is to replace the con- 
ception of uniform and widely extended 
strata by the recognition of numerous ir- 
regular and overlapping lenses, and to dem- 
onstrate that the later Carboniferous for- 
mations exhibit the character of coastal 
plain deposits rather than that of marine 
strata. The folios more recently published 
with reference to the Appalachian coal field’ 
are Nos. 34, 40, 44, 46 and 47, or the Buck- 
hannon, W. Va.; Wartburg, Tenn.; Taze- 
well, Va. and W. Va.; Richmond, Ky., 
