No organism wholly soft can be preserved.

Shells and bones decay and disappear when left on the bottom of the sea, where sediment is not accumulating.

We probably take a quite erroneous view, when we assume that sediment is being deposited over nearly the whole bed of the sea, at a rate sufficiently quick to embed and preserve fossil remains.

Throughout an enormously large proportion of the ocean, the bright blue tint of the water bespeaks its purity.