10 



NORTH AMERICAN FAUNA. 



[NO. 16. 



percentage of the coiuiuon species ami is, as expected, a stepi)ing stone 

 on wbicli restricted ISieria and Cascade species overlap. r)Ut the rep- 

 resentatives of the two ranges are not equally apportioned. The most 

 evident gap is on the north, Shasta sharing nmny more species in com- 

 mon with the Sierra than with tlie Cascades. Indeed, the resemblance 

 to the northern Sierra is so exceedingly close, jiarticularly in the mam- 

 mal faiuia, that from the standpoint of geographic distribution Shasta 

 could without violence be classed as i)art of the Sierra. This is the 

 more surprising in view of the fact that the g('ograi)liical gap between 

 Shasta and the Cascades is only half as broad as that between Shasta 

 and the Sierra. This subject is discussed in detail iu the chapters 

 entitled 'The l>oreal fauna and tiora of Shasta contrasted with corres- 

 ponding faunas and Upras of the Sierra and the Cascades;' 'Efticiency 

 of Klamath Gap as a barrier to Boreal species compared with that of 

 Pitt Eiver and Feather Kiver gaps collectively,' and 'Sources of the 

 Boreal faunas of Shasta and of the Sierra and the Cascades.' 



ITINERARY. 



Leaving the railroad at Sisson, at the west base of Shasta, we estab- 

 lished the first camp July 15, 1898, at a point known as Wagon Camp, 



Wa;;()ii Caiii]i. 



on the south alojte of the mountain, about a (juarter of a mile west of 

 Tanther (Jreek, at an altitude of 5,700 feet (tig. 1). Wagou Camp is.situ- 



