Photograph by ('.us A. Swan^on 



TIIFJR LIVING LIES BENEATH THE SNOW 



All nature loves kindness and trusts the gentle hand. Contrast these sheep, ready to fly 

 at the slightest noise, with those in the picture on page 396, peacefully feeding in close 

 proximity" to a standing express train. Every one appreciates a good picture of a living 

 animal more than the trophy of a dead one! 



fossil iiianinials shows conclusively that 

 numberless species have s])read from 

 their original homes across land brids^es 

 to remote tmoccnpied regions, where they 

 have become isolated as the bridges dis- 

 appeared beneath the waves of the sea. 



VAST NATURAL MUSEUMS OF EXTINCT 

 ANIMAL LIFE 



For ages Asia appears to have served 

 as a vast and fecund nurscrv for new 



mammals f ri nn which Xorth Temperate 

 and xVrctic America have been supplied. 

 The last and com]iaratively recent land 

 bridge, across which came the ancestors 

 of our moose, elk, caribou, prong-horned 

 antelope, mountain goats, mountain sheep, 

 musk-oxen, l)cai-s, and many other mam- 

 mals, was in the far Northwest, where 

 I'.ering .^traits now form a shallow chan- 

 nel iinl\- _'<S mik's wide separating Siberia 

 from Alaska. 



398 



