------------
|S |TRIAS, 5,000 ft. |First Mammalian (Marsupial); 2-gilled
|e | New Red Sandstone. | Cephalopods (Cuttle-Fishes,
|c | | Belemnites); reptilian Foot-Prints.
|o | |
|n | |
|d | |
|a | |
|r | |
|y | |
|---|--------------------------+---------------------------------------
|P |PERMIAN, 5,000 ft. |Earliest true Reptiles.
|a | +---------------------------------------
|l |CARBONIFEROUS, 26,000 ft. |Earliest Amphibian (Labyrinthodont);
|e | | extinction of Trilobites; first
|o | Coal. | Cray-fish; Beetles; Cockroaches;
|z | | Centipedes; Spiders.
|o | +---------------------------------------
|i |DEVONIAN, 18,000 ft. |Cartilaginous and Ganoid Fishes;
|c | Old Red Sandstone. | earliest and (snail) and freshwater
| | | Shells; Shell-Fish abundant; decline
|o | | of Trilobites; May-flies; Crab.
|r | +---------------------------------------
| |SILURIAN, 33,000 ft. |Earliest Fish; the first Air-Breathers
|P | | (Insect, Scorpion); Brachiopods and
|r | | 4-gilled Cephalopods very abundant;
|i | | Trilobites; Corals; Graptolites.
|m | +---------------------------------------
|a |CAMBRIAN, 24,000 ft. |Trilobites; Brachiopod Mollusks.
|r | |
|y | |
|---|--------------------------+---------------------------------------
|A |ARCHAEEAN, 30,000 ft. |
|z | Huronian. |Eozooen, (probably not a fossil).
|o | Laurentian. |
|i |--------------------------+---------------------------------------
|c |PRIMEVAL. |Non-sedimentary.
+------------------------------+--------------------------------------+

I submit, then, that so far as the largest and most general principles
in the matter of palaeontology are concerned, we have about as strong and
massive a body of evidence as we could reasonably expect this branch of
science to yield; for it is at once en