[152]

Maer June 6 /42/. (Grt. Oak!) Conditions requisite to preserve series of fossils to a distant period most corals & shells live in shallow water, therefore area of deposition must be so - deposition pretty quick else judging from rotten matter brought up by the lead fossils would decay - area of deposition extensive - for where can linear strips be found - prolonged subsidence afterwards for where can tops of strata be found must not be sand or pebbles -  How few deposits of cold period or of Miocene - yet shallow seas most favorable for life - How large area at present; land, open sea coasts such as vast coast of America where much sediment not accumulating all barren -  during elevation commencing with 50 fathoms denudation tends to destroy - subsidence of a thin bed, if not well covered will be denuded wherever brought up - there seems to have been subsidence during all great deposits corals in Siberia ripple in old Red - Coal-Beds - footsteps in new Red - upright trees in Oolite &c &c

[152v]

The stages of ammonites of D'Orbigny represent periods of subsidence after long intervals ＝ like stages of Fish of diff species of Miller in one of the divisions of Devonian. The very act of prolonged subsidence must tend to check supply of sediment; if checked, the deposit apt to be destroyed - Old lake or cavern formations, why have none been discovered: changes of condition in earth's surface = Brazil modern = Australia probably so = If Pampas was to go through the [system] & oscillations wh Europe has done being superficial wd be all destroyed:

Patagonian cliffs now 800 ft! - E. Indian Archipelago training up to be Europe W. Indies = How imperfect a series can these gaps show us. - How little can we tell when strata become land: Portland Dust Bed - Coal Beds - Uspallata! How long was the land dry