200 Field Columbian Museum — Ge'ology, Vol. i. 



one species of which has been described by J. A. Allen* as a passerine 

 bird of the family Fringillidae, the other by E. D. Copef as a species 

 of the order Grallae and tribe Limicolae. 



In conclusion, the hope may be expressed that if any specimens 

 of similar character are known they will be fully described, so that 

 more evidence may be at hand to clear up the difficulties encountered 

 in the study of this one. I have reports of the finding of at least two 

 other petrified eggs at different times in the same region, but have 

 been quite unable to verify the reports or see the specimens. A 

 systematic study of the forms of eggs seems also desirable, so that in 

 the future definite conclusions may be drawn regarding the order 

 or family to which a parent belonged when an egg is the only relic of 

 the parent to be obtained. 



•Bull. U. S. Geol. Surv. Terrs., IV, 1878. p. 443. PL I. 



tRept. U. S. Geol. Surv. Terrs., Vol. Ill, Book I, p. 754. PL LIX. 



