Gods of the Jungle by Nelson S. Bond

Deep in the ruined temple was a strange room; and when Ramey came out of it, many centuries of time had been wiped out.

In the darkness before the dawn, the sky was a vault of purple-black, hoarfrosted with the spangles of innumerable stars. The moon, in its dying quarter, was a silver scimitar dangling low on the horizon; the earth below, from this lofty eyrie, was a shadowy disc more sensed than seen.