28. Mountain. Carboniferous or mountain limestone. Limestone with marine shells and corals, etc.
L. Devonian.
29. Upper Devonian. Yellow sandstone, paving and roofing stone. Tribe of fish with hard coverings. No reptiles yet known.
30. Lower Devonian. Gray sandstone.
M. Silurian.
31. Upper Silurian. Tilestone. Oldest fossil fish yet discovered. Trilobites, etc.
32. Lower Silurian. Caradoc sandstone, etc. No land plants yet known. Footprints of tortoise, etc.
SYNOPSIS.
| Post-Tertiary. |  | Tertiary or Cainozoic. |  | Mesozoic. |
| Pliocene. | ||||
| Miocene. | ||||
| Eocene. | ||||
| Cretaceous. |  | Secondary or Mesozoic. | ||
| Jurassic. | ||||
| Triassic. | ||||
| Permian. |  | Primary or Paleozoic. | | Paleozoic. |
| Carboniferous. | ||||
| Devonian. | ||||
| Silurian. | ||||
| Cambrian. |