12 with the arms 38 fully retracted to enable relatively unrestricted movement into the wellbore 12 upon reaching a depth in the wellbore 12 below the zones shown as 20 and 22 in fig1 the system operator can enter a command into the surface electronics 30 in fig1 to extend the arms 38 and the tool 10 can be slowly pulled out of the wellbore 12 while recording with respect to depth the measurements made by the tool 10 each arm 38 includes a plurality of temperature sensors such as those shown generally at 42a 42b 42c and 42d positioned at spaced apart locations along each arm the temperature sensors can be of a type known in the art such as thermistors the sensors 42a 42d are each connected to a temperature measuring circuit shown at 46 which generates a signal corresponding to the thermistor resistance and thereby the temperature of each sensor 42a 42d when the arms 38 are fully retracted the temperature sensors 42a14 42d are positioned into contact with a wall of the lower end 36a because the lower end 36a is constructed from a thermally conductive material differences in temperature across the wellbore will be dissipated within the lower end 36a and the temperature sensors 42a 42d will each be at substantially the same.