Re: Thin egg shells

[Crpntr@ix.netcom.com (Kenneth Carpenter)]

Chris Illes wrote: 
>Is it possible that the eggs were leathery like some lizard/snake eggs 
and that
>fossilization calcified (or otherwise hardened) the shell pieces? 
>Considering the egg size to thickness, how does this compare with say 
an Ostrich
>egg? Are the ratios of overall size to shell thickness similar? Emu or 
Moa eggs?

No it is not possible that the eggs had a leathery covering, because a 
leathery covering has little or
no calcite crystals.  The ultra- and microstructures  of fossil eggs 
often show little or no
diagenesis indicating original shell.  Diagenetically altered shell 
lacks the organized crystalline
columns seen in original shell.  The length of ostrich eggs varies 
according to species (fossil
except where noted) Struthio pannonicus (n=1) 220 mm long, 2.6-3.4 mm 
thick, S. chersonensis
(n=1) 180 mm l, 2.6-2.7 mm t, S. anderssoni (n=12) 166-188.5 mm l, 
2.1-2.3 mm t, S. camelus
australis  (modern) 127-160 mm l (n= 166) 1.6-1.1 mm t; Cassowary (n=1) 
about 133 mm l, 0.86
mm t, emu (n=1) 144 mm l (no data available on thickness).   I don't 
have data for moa eggs.