Note 411 — GEOLOGICAL ILLUSTRATIONS, (continued 3)

The dryness depends chiefly, if not entirely, on the fissures or divisions in the rocky base of the soil; for, in some parts of Sologne in France, as stated by Mr Arthur Young, and in sundry districts of England, chalk and limestone bottoms are occasionally observed to be retentive and wet. Undergrounds, formed of chalk or limestone, have frequently a thin covering of vegetable mould, from their being, in some cases, over close and wet, and in others over open and dry; the former condition being unfriendly to vegetation and the formation of mould, and the latter too readily permitting its departure when formed, or otherwise favouring the decomposition and waste of that material.