SURVEY OF THE SAH JUAB REGIOB . 1875 , 
This was an unusually ^ventful year for me • On May 1st, 
1875, I was appointed Assistant Geologist on the Survey of the 
Territories, salary $2400.00, and given charge of the San Juan 
Division of the Survey, with George B. Chittenden as Topographic 
Engineer. 
The spring season was spent in Washington finishing up 
the reports and illustrati ons of the previous year, and editing 
and supervising engraving and printing wori:. Early in June my 
party assembled at Denver to arrange for the march into the San 
Juan Country, Southwestern Colorado and adjacent areas in Arizona 
and Utah. My report as Geologist is published in the Report of 
the Survey of the Territories for 1875, pages 237-276, and separate 
accounts of events of particular interest appear in other connections. 
The report on the ancient ruins of the region, which was published 
in the 1876 report, pages 383 - 408, is the most important of the 
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latter. My career as an archaeologist and anthropologist began 
with the study of these most interesting antiquities. 
There were many features of interest, geological and 
otherwise in the summer T s explorations, among which the most im- 
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portant was my observations of the laceolite (stone late) intru¬ 
sions of lava among the sedimentary strata. This feature is 
recorded in "Contributions to the History of American Geology" by 
George P. Merrill, separate publication from the Report of the U.S. 
Rational Museum for 1904, page 601, with portrait. For Professor 
