^{page 280 note 1} The phrase “impotence of rain,” I have applied onlytothe action of mere rain on compact rocks and grass-covered land, and not to torrents, charged with solid abrading matter, and acting on exposed gravel, loose stones, or soft materials. When using the phrase, I was not alluding to volcanic oralpine districts where conditions are, or have been, exceptionally favourable to atmospheric denudation.

^{page 282 note 1} There are several very important points in Mr. Jukes' letter, the consideration of which I must reserve for a future, and more systematic communication.