Figure F21. Summary of spectral gamma-ray logs from the hostile environment natural gamma-ray sonde, plotted vs. depth for the open-hole logged interval. From left to right, columns are core recovery, total gamma radiation (HSGR) and computed (uranium-free) gamma radiation (HCGR), uranium, thorium, potassium and caliper, logging units, lithostratigraphic units, and biostratigraphic ages.