Marcu 7, 1884. ] 
for instance, stretch from Missouri to Arctic 
America, and are enclosed in sediments of simi- 
lar character throughout these limits. Aside 
from defects of particular arguments, and 
aside from any weight attributable to this 
essay, the question is one which will undoubt- 
SCIENCE. 
293 
edly provoke competent and deliberate discus- 
sion. Mr. Scribner’s monograph is well writ- 
ten, with some local diffuseness, and an occa- 
sional sentence of intolerable length, but, 
on the whole, a timely, suggestive, and pleasant 
little volume. 
INTELLIGENCE FROM AMERICAN SCIENTIFIC STATIONS. 
GOVERNMENT ORGANIZATIONS. 
Geological survey, 
Rocky Mountain division. — Upon the organization 
of the survey, the area of the United States was di- 
vided into eight districts, in order that the progress 
of the work might be systematically facilitated. Of 
the four western districts, the ‘ Rocky Mountain dis- 
trict ’ includes the state of Colorado and the territories 
of New Mexico, Wyoming, and Montana. 
Geologic work. — Colorado has been the prin- 
cipal field of geologic activity in the district; and the 
work has been carried on under the supervision of 
Mr. S. F. Emmons, who is the geologist in charge, 
with headquarters at Denver. The mining-geology 
of the state has been made the subject of special 
study, and the investigations have been confined 
- mainly to questions of direct economic importance. 
Prior to 1883 the work done was principally in the 
Leadville and Ten-mile regions. Last season an ex- 
amination of the Silver Cliff mining-district was un- 
dertaken. The geologic work was begun by Mr. 
Whitman Cross about the Ist of July, and was car- 
ried on through the summer, and completed in 
September. The topographic work had been previ- 
ously completed. The preparation of the geologic 
map was intrusted to Messrs. Cross and Chapman, 
assistant geologists. Messrs. Jacob and Eakins were 
detailed to report on the mines and ore-deposits, 
under the personal supervision of Mr. Emmons, Mr. 
S. S. Sackett was engaged in gathering statistics as 
to the reduction of the ores of the district, and 
secured material for a chapter on the mills and reduc- 
- tion-works of the district. 
The report on this mining-district will be of espe- 
cial value, as the Silver Cliff is a mining-camp of 
abortive processes, a true history of which may well 
serve as a warning, by pointing out the errors, which 
there led to the failures in mining and in the reduc- 
tion of the ores, 
From the Silver Cliff district a short trip was made 
to the Sangre de Christo range, which lies on the 
opposite side of the valley. This was made with a 
view to determine the geologic relations of the Silver 
Cliff ore-deposits to the rocks of the range. Some 
field-work was also done by Mr. Cross on the mesozoic 
rocks exposed in the vicinity of Golden and of Mor- 
rison. In the Denver coal-basin progress was some- 
what retarded by the absence of Mr. Karl, who has 
charge of the topographic survey of the region. 
Although temporarily suspended during the summer, 
work in this basin can be carried forward during the 
winter months, when the snow causes the abandon- 
ment of the field in the mountainous sections of the 
state. The map of the basin is toinclude some thirty 
square miles, on a scale of one mile to one inch. In- 
formation on the subject of the artesian wells in this 
basin is being secured, and will be embodied in the 
report. Voluminous rock-collections were made dur- 
ing the season, especially in the Silver Cliff district; 
and a special trip was made to Buffalo Peaks for the 
collection of typical specimens of hypersthene-an- 
desite. 
Besides the field-work, considerable office-work was 
accomplished. The notes on the Ten-mile district 
were worked up, and a geological map and sections of 
the area were made. Manuscript for the following 
monographs by the ‘Rocky Mountian division’ are 
in advanced stages of preparation: viz., 1°, Geology 
and mining industry of Leadville, by S. F. Emmons 
(an abstract of this paper appeared in the second 
annual report of the survey); 2°, Geology and mining 
industry of Ten mile district; 3°, Geology and min- 
ing industry of the Silver Creek district; 4°, The 
basaltic mesas near Golden, and their relation to 
the contiguous tertiary and cretaceous beds. Dur- 
ing the season the bulletin on hypersthene-andesite, 
by Mr. Whitman Cross of this division, was published. 
Laboratory work. — The laboratory at Denver 
is in charge of Mr. W. F. Hillebrand, chemist, who 
has been busy with the chemical and lithological ex- 
amination of the rocks collected in the district, and 
on the ores from the various mining-districts. Some 
of the details of his work have already been given 
in Science. Mr. Whitman Cross has carried on the 
microscopical examination of the numerous thin rock- 
sections made of the rocks collected in the district. 
Topographic work.— Mr. Anton Karl has 
been carrying on the topographic surveys in the dis- 
trict, and during the season of 1883 was in the Elk 
Mountains, mapping the Gunnison mining-region. 
His triangulation was based on Snow Mass and West 
Elk Mountains, two points located by the Hayden 
survey. These were occupied, and a system of tri- 
angulation was extended from them over the whole 
area surveyed. The principal mines in the Ruby 
basin, lying between Mount Owen and Irwin Peak, 
were all located, as well as Anthracite Mountain and 
the property of the Denver and South Park coal 
company. Topographical data were obtained for 
¢ 
