INTRODUCTION 17 



floras. These three groups of Alleghanian species must have 

 three different sets of causes limiting their distribution. They 

 await satisfactory determination. 



III. The Canadian Zone. Due principally to the recent 

 investigations of Mr. W. DeW. Miller in extreme northern and 

 northwestern New Jersey, a distinctly Canadian element has 

 been found, especially in the high-forested plateau between 

 Bearfort and Wawayanda Mountains, where the altitude 

 varies from 1200-1400 feet. This element appears in many 

 other swamps and bogs of Sussex County. It is quite possible 

 that other species may yet be found, and undoubtedly many 

 new stations for the known species remain to be discovered. 

 Not even half the likely country has been visited, and none of 

 it has been thoroughly studied. The following species are 

 characteristic of the Canadian Zone. Those whose breeding- 

 is regarded as casual are omitted. 



?Wilson's Snipe Blackburnian Warbler 



?Solitary Vireo Northern Water-thrush 



Nashville Warbler Canadian Warbler 



Black-throated Blue Warbler Brown Creeper 



?Magnolia Warbler Hermit Thrush 



It seems curious that the distribution of these Canadian 

 forms in our territory is the most normal and the least 

 anomalous. The Hermit Thrush, however, nests commonly 

 in the hottest and driest pine-barrens of Long Island, and it is 

 very rare in the one section where all the other species occur. 

 The others require no comment. Anyone who has had field 

 experience in the heart of the Canadian Zone would immedi- 

 ately understand their occurrence in the region where they 

 are found. It is astonishing, however, to find the Hooded, 

 Golden-winged, and Canadian Warblers equally abundant in 

 the same swamp, and to find all three disappearing southward 

 at the same rate. When it is realized that they are taken as 

 indices of three different life-zones, it is evident that their 

 occurrence together cannot be explained by isothermal lines. 



