Re: Egg questions (was: Re: Allosaur baby faces)

[Matias Soto <soto@adinet.com.uy>]

Phil wrote:

> SEM (scanning electron microscopy) can readily distinguish "leathery"
> fossilized eggs from "hard shell" fossilized eggs.  "Hard shell" eggs
> have tightly interlocked calcite crystallites, with only a little
> interstitial protein forming the matrix.  "Leathery" eggs are mostly
> protein.  IIRC, there is a continuum between leathery eggs and hard shell
> eggs, with the abundance of calcite crystallites being the variable.
>
> Regarding the flattened side on the _Tacuarembovum oblongum_ egg, try
> this experiment:  Take a chicken egg and place it in a pan with a couple
> millimeters of vinegar in the pan.  Wait a day and remove egg and let it
> dry out.  The bottom of the egg shell will be flattened.  Meaning that
> even hard shell eggs can display this feature (groundwater can be acidic,
> particularly if the egg is sitting in a puddle of rotting vegetation).

Interesting... That really helps.
Thanks!

Matías