2 The American Geologist. January, 1905 
logical surveys to be carried on under the auspices of the 
Harvard School of Mining. 
In the summer of 1869, professor Pettee made a geolo- 
gical and topographical survey of South Park, Colorado, and 
during the year 1870-71, having been granted a leave of 
absence from Harvard, he became connected with the Cali- 
fornia State Geological Survey. Besides making a study of 
gold-bearing gravels of CaHfornia, he undertook systematic 
work in correction of the determination of altitudes by means 
of the barometer. Some of the results of this investigation, 
collected from the detailed reports of the survey, were pub- 
lished by authority of the California State Legislature in 
1874, entitled Contributions to Barometric Hypsometry, with 
Tables for use in California, to which a supplement was 
added in 1878. Prof. Whitney's estimate of the onerous 
labor, the accuracy and perseverance of Prof. Pettee's work 
in this undertaking appears in the prefatory note to the 
volume above mentioned. 
From 1 87 1 to 1875 in addition to other duties Prof. Pet- 
tee gave instruction to an elective section of undergraduates 
in physical geography, geology, and meteorology at Harvard, 
but before 1875 the conditions of the gift supporting a school 
of mining at that institution were altered and provisions for 
a special instructor in these subjects was with drawn. 
In 1875 professor Pettee was appointed to a professor- 
ship of mining engineering and related subjects in the Uni- 
versity of Michigan, a position which he held with various 
changes of title, until his death. 
In the first semester of 1879-80, Prof. Pettee was granted 
leave of absence from the University of Michigan to continue 
his investigations of the auriferous gravels of California. His 
report on that work was published as an appendix to the 
first volume of Whitney's "Contributions to American Geol- 
ogy." .It has ])een adjudged to show that careful examina- 
tion of phenomena, weighing of evidence, and painstaking 
accuracy, which those best acquainted with professor Pettee 
always expect in papers prepared by his hand. 
The annual transactions of the American Institute of 
Mining Engineers have been submitted to professor Pettee 
for many years, for critical proof-reading and correction. Of 
