F. H. Olmsted 1980 This report consists of 310 temperature logs made in 266 wells and test wells in the Yuma area, Arizona and California during 1963-69. The work was done as part of a geohydrologic study, the results of which are reported in the 1973 U.S. Geological Survey Professional Paper 486-H; Geohydrology of the Yuma Area, Arizona and California, by Olmsted, Loeltz, and Irelan. Most of the logs are plotted from temperatures measured with two Whitney thermistors at depth intervals of 2 to 20 feet in downward succession in each well or test hole, using land surface as datum. A few logs were made with a truck-mounted wireline logger using thermistor probes and continuously recording equipment. All measurements were in degrees Fahrenheit, later converted to degrees Celsius, and were calibrated with a mercury-in-glass thermometer. Accuracy of most of the measurements was + or - 1.0F and precision was about + or - 0.2F. (USGS) application/pdf 10.3133/ofr80335 en Temperature logs of wells and test wells in the Yuma area, Arizona and California reports