I. Palaeozoic Or Primary Rocks

1. Laurentian. (Lower and Upper.)

2. Cambrian. (Lower and Upper, with Huronian rocks?)

3. Silurian. (Lower and Upper.)

4. Devonian, or Old Red Sandstone. (Lower, Middle, and Upper.)

5. Carboniferous. (Mountain-limestone, Millstone-grit, and Coal-measures.)

6. Permian. ( = the lower portion of the New Red Sandstone.)

II. Mesozoic Or Secondary Rocks

7. Triassic Rocks. (Bunter Sandstein, or Lower Trias; Muschelkalk, or Middle Trias; Keuper, or Upper Trias.)

8. Jurassic Rocks. (Lias, Inferior Oolite, Great Oolite, Oxford Clay, Coral Rag, Kimmeridge Clay, Portland Stone, Purbeck beds.)

9. Cretaceous Rocks. (Wealden, Lower Greensand, Gault, Upper Greensand, White Chalk, Maestricht beds.)

III. Kainozoic Or Tertiary Rocks

10. Eocene. (Lower, Middle, and Upper.)

11. Miocene. (Lower and Upper.)

12. Pliocene. (Older Pliocene and Newer Pliocene.)

13. Post-tertiary. (Post-pliocene and Recent.)