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Recent Literature. fOctober 



in the interior basin of California, occupying the valley of the Sacramento 

 and San Joaquin Rivers, and a branch extends along the coast between 

 Monterey and the Santa Barbara plain (p. 30). 



The 'humid' division of the Lower Sonoran corresponds to what has 

 been commonly termed the Lousianian Fauna, or the 'Austroriparian' 

 of some writers. "It begins on the Atlantic seaboard at the mouth of 

 the Chesapeake Bay and stretches thence southwesterly, embracing the 

 alluvial lands of the South Atlantic and Gulf States below what geol- 

 ogists know as the 'fall line,' rising i-n the Mississippi bottom as far as the 

 junction of the Ohio with the Mississippi, and following the' former in a 

 narrow strip to the point where it receives the Wabash. On the west side 

 of the Mississippi it crosses Arkansas, reaching southern Missouri and 

 southeastern Kansas, and spreads out over Indian and Oklahoma Terri- 

 tories and Texas, where it loses its moisture and merges insensibly into 

 the arid Sonoran" (p. 28). The 'arid' Lower Sonoran extends thence 

 westerly, "covering southern New Mexico and Arizona south of the 

 plateau rim (sending a tongue up the Rio Grande to a point above 

 Albuquerque), the west side of which it follows northerly to the extreme 

 northwestern corner of Arizona and the southwestern corner of Utah 

 (where it is restricted to the valley of the lower Santa Clara, or St. 

 George Valley), and thence westerly across Nevada, .... and thence 

 curving southwesterly .... covers the whole of the Mohave and Colorado 

 Deserts and all the rest of southern California except the mountains." It 

 also includes most of the peninsula of Lower California, and occupies a 

 small area in the San Joaquin and Sacramento Valleys (p. 28). Respect- 

 ing Lower California he adds: "It is evident, however, that the peculiar 

 fauna of the peninsula of Lower California entitles it to rank as a minor 

 subdivision of the Lower Sonoran Zone. It is in effect an insular fauna of 

 recent origin, bearing the same relation to that of the main land as do 

 several of the adjacent islands" (p. 30). 



Between the Boreal and Sonoran Regions Dr. Merriam recognizes what 

 he terms a ' Neutral or Transition Zone,' which has also a humid and an 

 arid division. The former corresponds to what is generally known as the 

 Alleghanian Fauna, while the arid division is its western equivalent. It 

 forms for the most part a pretty broad belt, characterized by the overlap- 

 ping of boreal and 'Sonoran' types. This 'Transition Zone,' as described 

 in the text and as laid down on the accompanying map, suggests one or two 

 troublesome queries. How, for example, is this 'Transition Zone' to be 

 classified — as a part of the 'Boreal Region' or as a part of the 'Sonoran 

 Region.?' or does it belong to neither.? If so, what is its status? Obvi- 

 ously, so far as nomenclature goes, it is that of a minor region interposed 

 between, and thus wholly separating, two primary regions! It is appar- 

 ently co-ordinate in rank with the 'Upper Sonoran' and the 'Lower Sono- 

 ran' Zones, respectively, and also with the 'Hudsonian' and 'Canadian' 

 zones. While we are willing to accord it this rank, and are thus in agree- 

 ment with our author so far as the facts are concerned, we should much 



