 How many caves had Garmon and Rolf traveled through before their crash?
Sisko Rolf's stocky body was a blur of motion as he cut the rocket jets, doused the twin searchlights, and switched over to the audio beams that served so well on the surface when blind flying was in order. Somehow Rolf found the strength to wrap his fingers around the control levers and snap on a quick burst from the landing rockets. The floors of the thirty-seven caves through which they had so carefully jetted were a splintered, creviced series of canyon-like wastes, and as he ascended the rarefied atmosphere of the higher levels would spell death. "They may have found the sunken seas of Mars," thought Rolf as he moved alertly forward, "water that would give the mining domes new life."
 thirty seven
 thirty seven  forty seven  thirty  forty