[F10r]

tend to be obliterated by rain & other atmospheric agencies. There is some analogy between the formation of the ledges, as here supposed, & that of the ripples of wind-drifted sand, as seen & described by Lyell.*(21)

[Earthworms, p. 282: "Any projection beneath a ledge would not afterwards receive distintegrated matter from above, and would tend to be obliterated by rain and other atmospheric agencies. There is some analogy between the formation, as here supposed, of these ledges, and that of the ripples of wind-drifted sand as described by Lyell.*"]

[slip of paper pasted on:] (But sheep seem often graze on horizontal lines on very gentle slopes, so that such surfaces which are then faintly marked by them, as can be seen, but only when viewed from a distance, like [text excised] marked. It is probable that animals move along a slope