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- Public30
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- Geological Survey (U.S.)✖[remove]30
- Brooks, Alfred H. (Alfred Hulse), 1871-19248
- Witherspoon, D. C4
- Marshall, R. B. (Robert Bradford), 1867-19493
- Bagley, James Warren, 1881-19472
- Berry, R. W2
- Giffin, C. E2
- Sargent, Rufus Harvey, b. 18752
- U.S. Coast and Geodetic Survey2
- Abercrombie, W. R.--(William Ralph),--b. 18571
- Anderson, C. G. (Cleland George), 1879-1
Current results range from 1898 to 1922