Discusses the geological origin of terraces.
Mentions R. I. Murchison’s paper ["On the superficial detritus of Sweden", Q. J. Geol. Soc. Lond. 2 (1846) pt 1: 349–81].
Comments on Tertiary beds of South America. Doubts that durable formations are now accumulating. Discusses formation of trap-rock. Notes effect of decomposition of lava; discusses action of submerged gravel on underlying rock.