CHAP. XX. FACTS OF MIGRATION. 261 



subject, no doubt, to many exceptions, the birds who have 

 come from tlie longest distance arrive the earliest. The facts 

 of migration are, however, so many, and the theories which 

 they suggest are so various, that we must bring this rambling, 

 if not irrelevant, chapter to an end, and return to the narra- 

 tive of our doings in the valley of the Petchora. 



OLD RUSSIAN SILVER CROSS. 



