 |
| |||
| bed of clay; clay layer; impervious soil | |||
| clay bank; clay seam; clay stratum | |||
| clay bed; clay pan | |||
| layer of clay | |||
| |||
| argillaceous sediments | |||
|
Tonschicht : 9 phrases, 6 sujets |
| Charbon | 1 |
| Exploitation minière | 4 |
| Général | 1 |
| Science des matériaux | 1 |
| Sciences de la vie | 1 |
| Transport | 1 |