Note 161 — Chapter XIX
Reading edition
"On the South American coast, where tertiary and supra-tertiary beds have been extensively elevated, I repeatedly noticed that the uppermost beds were formed of coarser materials than the lower; this appears to indicate that, as the sea becomes shallower, the force of the waves or currents increased."—Darwin's Observations, pt. ii., 131. "Nowhere in the Pampas is there any appearance of much superficial denudation."—Pt. iii., 100.