Re: Egg-sistential question

[Rich Travsky <rtravsky@UWYO.EDU>]

On Tue, 24 Sep 1996, Rob Meyerson wrote:

> A question on dino-eggshells has been put to me recently, and I
> thought I'd put it to the group.
> 
> When one looks at modern reptiles, practically all of them lay eggs
> with a leathery outer shell.  This type of egg is also laid by the
> dinosaurian cousin, the crocodile.  However, this does not apply to
> birds, who lay eggs with very hard shells.
> 
> Are there any thoughts as to when the bird-like egg first evolved?  Is
> it purely an Avian trait, or can it be extended to most/all dinosaurs?

And further out of curiousity, can one tell whether fossilized eggs were
leathery or hard?

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