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Queries

absence of organic R.

Will pure water with no Carbonic acid dissolve any Lime? ratio Temperature to dissolution of Carb. Acid?

About gypsum? —

Analysis of sea-water for Phosphates — all protoplasm must contain some & so I suppose sea-water must.

Proportion of Phosphates in Corals & Mollusca. Crustaceans.

Will i.e are these cases known? Etheridge. Cartilage or epidermic layer or Chiton silicify, if not we could have no fossils —

Bone will silicify & wood & I thank mould. R. Brown. (a)

Proportion of carbonic acid & of lime in Tropical compared to cold seas —

Deep sea-water of Tropics is — cold.

Aboriginally carbonate of lime wd. have been distributed & disseminated, like other earths, in crust of earth; for it is admitted that all great beds of

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Has carbonic acid any relation to holding silica in solution?

{Siliceous Diatoms & skeletons of sponges wd be preserved — {Slices of Cambrian rocks ought to be examined.—

What is the composition of the shells of Crustaceans. Of what was the carapace of Trilobites composed? See Burmeister) This cd be a decisive point; for if only believed to be chitinous my paper wd be useless—

My point is what chance is there of fossils being preserved, which do not contain any calcareous matter in their integument or skeletons — As they wd decay soon there wd not be a good chance of caste, & then comes query wd they often be silicified, ie replaced molecule by molecule by silica?

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Lime are due to organisms which absorb lime from sea-water. — We may expect metamorphic rocks in which there is reason to believe aggregation occurs.—

Davidson on Trimerillidæ.— (Does not Belt make some remark to same effect?)— Duncan the most ancient corals known are they less calcareous

[Thomas Davidson. 1874. On the Trimerillidæ, a Palæozoic family of the Palliobranchs or Brachiopoda.]

No doubt warm no no springs might have brought to surface C. of lime pure & then some beds have been formed.— What is temp. of springs charged with C. of lime? It seems impossible that there cd have been beds of pure or nearly pure C. of lime deposited at a period when water did not hold lime in solution

Häckels Medusæ & feathers of Archeopteryx show that soft substances may leave impression; but then these can probably be destroyed by very slight movement in the particles of the rock, as by pressure which induces cleavage.