502 071 Female Pheasants assuming the Male Plumage. 



Geology obtains its materials from mineralogical geography, 

 whose'general results it selects and combines, in the same manner 

 as state policy does with the results of civil geography. The 

 advancement of the one, therefore, depends on the progress of the 

 other ; and although it may be advantageous to science, from 

 time to time, to exhibit a correct view of its progressive advance- 

 ment, as it is profitable for the traveller to stop sometimes and take 

 a retrospective view of the country he has passed, geology has 

 nevertheless to expect improvement principally from a patient 

 and laborious investigation of single districts. There are but 

 few who, by a glance, can determine general relations and throw 

 light upon science, as there are but few travellers who are qua- 

 lified to give any instructive information concerning the social 

 condition of a country : On the contrary, any one provided with 

 the necessary knowledge, may, by an accurate and detailed exa- 

 mination of a district, contribute, if not general views, facts that 

 serve as a foundation for the great geological edifice. And, any 

 one who reflects how much time and perseverance are necessary 

 for examining the geognostic character of even a limited district, 

 especially if its interior is not laid open by mines and natural 

 sections, will agree with us, that this investigation, like that of 

 the character and customs of a people, must chiefly be the work 

 of an inhabitant. 



On Female Pheasants assum^mg the Male Plumage. By M. 

 Isidore Geoffroy St Hilaire. 



Jl HE AS ANTS somctimcs occur in the woods, as well as in a state 

 of domestication, which, from the dulness of their colours, while 

 at the same time they possess the male plumage, were long con- 

 sidered as males in a diseased state, or with their feathers soiled 

 and tarnished ; but it has been ascertained that they are hen 

 birds with the plumage of males ; and, in fact, Vicq d'Azyr 

 and Mauduit, from the inspection of the sexual organs in such 

 birds, have placed this curious fact beyond the reach of doubt. 

 Mauduit, in his account of it, in the Encylopedie Methodique, 



4 



