"We felt ourselves necessarily carried back to the time when the schistus on which we stood was yet at the bottom of the sea, and when the sandstone before us was only beginning to be deposited, in the shape of sand or mud, from the waters of a superincumbent ocean. An epocha still more remote presented itself, when even the most ancient of these rocks, instead of standing upright in vertical beds, lay in horizontal planes at the bottom of the sea, and was not yet disturbed by that immeasurable force which has burst asunder the solid pavement of the globe.... The mind seemed to grow giddy by looking so far into the abyss of time."

-- James Playfair, Transactions of the Royal Society of Edinburgh, vol. V, pt. III, 1805.
[quoted by Margaret Carruthers, Natural History, June 1999]