| A | B |
|---|
| humus | leftover decomposed plant or animal matter |
| horizon | layer of soil differing from layers above or below it |
| topsoil | the top layer of soil rich in humus and minerals |
| subsoil | hard layer of clay and minerals that lies beneath top soil |
| pore space | the space between soil particles |
| permeability | the rate at which water can pass through a mineral |
| moraine | rock debris carried and deposited by a glacier |
| erratic | an isolated boulderleft behind by a glacier |
