Life of David Dale Owen, M. D. 69 
(to-wit, on the 17 Sept.) I had reached the mouth of Rock 
river ; engaged one hundred and thirty-nine sub-agents and 
assistants ; instructed my sub-agents in such elementary 
principles of geology as were necessary to the performance of 
the duties required of them ; supplied them with simple min- 
eralogical tests, with the application of which they were made 
acquainted ; organized twenty-four working corps, furnished 
each with skeleton maps of the townships assigned to them 
for examination and placed the whole at the points where their 
labors commenced, all along the line of the western half of the 
territory to be examined. Thence the expedition proceeded 
northward, each corps required, on the average, to overrun 
and examine thirty quarter sections daily, and to report to 
myself on fixed days at regularly appointed stations : to receive 
which reports and to examine the country in person, I crossed 
the district under examination, in an oblique direction, eleven 
times in the course of the survey. Where appearances of par- 
ticular interest presented themselves I either diverged from 
my route in order to bestow on them a more minute and 
thorough examination, or when time did not permit this I 
instructed Dr. John Locke, of Cincinnati (formerly of the 
geological corps of Ohio, and at present Prof, of Chem. in the 
Medical College of Ohio) whose valuable services I had been 
fortunate enough to engage on this expedition, to inspect these 
in my stead." 
3. The above work having been completed to the satisfac- 
tion of the department, and having demonstrated the enterprise 
and energy of Dr. Owen, he was appointed in 1847 U. S. 
Geologist and directed to make a survey of the Chippewa land 
district. The Preliminary Report made in 1848 to the Hon, 
R. M. Young, then commissioner of the land oflice, occupies 
134 8vo pp., besides presenting 323 lithographs from Dr. 
Owen's sketches, and numerous maps, diagrams, <kc. 
4. The above preliminary reconnoissance was by instruc- 
tion from Washington extended to a more full survey of the 
N. W. territory, embracing chiefiy Wisconsin, Iowa and Min- 
nesota, which occupied five years of field work, and a final 
year of laboratory and office work, being then continued from 
1847 to 1852 both inclusive. The full report in manuscript 
having been approved, Congress made a large appropriation 
for its printing and illustration in a high style of art, entrust- 
