Figure F20. Summary of spectral gamma-ray logs from the hostile environment natural gamma-ray sonde plotted on an expanded depth scale to highlight variations in the interval logged through pipe. From left to right, columns are core recovery, total gamma radiation (HSGR) and computed (uranium-free) gamma radiation (HCGR), uranium, thorium, potassium, logging units, lithostratigraphic units, and biostratigraphic ages.