Arenl Work of the U.S. Geological Survey. — Me Gee. 3T7 
\ Concordance of stratifiCcation. 
I Dockum division.— 400 feet. 
Double Muuiitain division. 
Tliickiiesis, 'JOrr) feet. 
Clear Fork division.— 1875 feet. 
Nota bene.— At the base of tlie divis- 
ion — about the lirst 800 feet— inverte- 
brate fossils have been found at Mil- 
itary crossing and Godwin creek 
(Baylor Co.), and at Camp creek 
(Archer Co.). A few vertebrates 
have been found also scattered at 
about the same lower horizon. 
Wichita division.— 1800 feet. 
2^o/n bene.— In the upper part, at the 
head of (iodwin creek, a Dyassic flora 
with Walchia has been found, with 
vertebrate fossils such as : reptiles, 
V)atrachians and fishes. 
. f Albany division.— 1180 feet. With the 
a I Dyassic fauna of Nebraska City. 
« I Cisco division.— 840 feet. 
^ I Dyassic mixed with Carboniferous 
g 1 fossils. 
f Concordance of stratification. 
I Variegated marls.— .500 feet. 
£ Sandstone, dolomite and red clay; 
1^^ I extendintr from Antelope hills to 
K [ Rocky Dell creek.- 1000 feet. 
^ ^ y- \ Red marls inclosing gypsum, salt, 
2 B < I clay and dolomite, extending from 
"^251 Natural Mounds to Antelope hills. 
^H 1 —1500 feet. 
t» — 
M -i. f Vermilion marls and clays, inter- 
? H 3 I stratified with beds of red marly 
E- ^ ! sandstone, with green spots; es- 
§ n I tending from Cross Timbers to 
p; 5 i Rock Mary and Natural Mounds. 
cK 1 —3000 feet. 
Xota 6ewe.— This formation embraces 
the lower portion of the Clear Fork 
division — about 300 feet — and the 
Wichita, Albany and Cisco divisions 
of Mr. Cummins. 
Canyon division.— 980 feet. 
(. With a Carboniferous fauna. 
Red and blue clay with conglomerate ; 
extending from Topofki creek to 
Cross Tiiiibers, west of old FortAr- 
buckle or Beaversville. — 1000 feet. 
Break. Unconformity. 
Cakbonifkuous 
System. 
^ Limestone of Delaware 
Ridge, with a Carbon if- 
/ erousfauna. 
THE AREAL WORK OF THE U. S. GEOLOGICAL 
SURVEY.* 
By W. J. Mc(iEE, Washington. 
When the U. S. Geological Survey began its work some 1)5 
years ago, only a small portion of the public domain was mapped 
out, so that the first thing to be done was to prepare a topographi- 
cal map. It was not considered then nor is it considered now, 
necessary' to prepare a detailed map ; all that was and is desired 
is a map giving the main landmarks and the contour lines, sur- 
veyed and drawn with just sufticient accuracy for the scale of the 
map and no m<n-e. It was at fiinst decided to use the scale of four 
miles to the inch throughout most of the domain and employ the 
scales of two miles and one mile to the inch in more important 
centers. However, the methods of survey have been so much im- 
proved since then, and the cost per mile so much reduced in con- 
* Abstract of a paper read before tlip American Institute of ^riii- 
ing Engineers, at the heading Meeting. 
