REGION AT HEAD OF LAKE MICHIGAN. 149 



to succeed as well on this formation as any other tree if we ex- 

 cept the cottonwood, yet in the cold winter of 1898 and 1899 

 referred to before a number of beautiful specimens of Gleditsia 

 triacanthos were winter-killed on these lowlands. Fraxinus 

 quadrangulata, after a period of thirty-five years, is not more 

 than from nine to ten inches in diameter, and about 18* to 20 

 feet high, but seemingly healthy, only dwarfed. Nyssa multi- 

 flora and Fagus ferruginea die out after a few years of struggle. 

 As most of this formation is within the influences of the smoke 

 of the city of Chicago, no reference will be made to evergreens, 

 as all of them succumb after a longer or shorter period. 



In discussing Introduced Vegetation I also desire to call 

 attention to a specimen of yellow wood (Cladrastis tinctoria) 

 that stands on the top of the Morain about sixteen miles west of 

 Chicago. This tree is more than twelve inches in diameter, and 

 the only one found of any consequence in the entire region. In- 

 troduced to the Glacial Drift it lingers along for a few years and 

 then succumbs. That no reference has been made to Introduced 

 Vegetation on the Alluvial Formation is largely due to the fact 

 that these formations have either been covered with manufactur- 

 ing, or with the homes of the laboring man where inhabited, and 

 consequently no large gardens are found in this district that 

 naturally would contain a variety of Introduced Vegetation. 



Most of the species introduced to the Glacial Deposit are 

 found in the parks of Chicago. I may also here mention the 

 attempt made of introducing Rhododendrons and Azaleas to our 

 parks and gardens, but always with failure, even when the 

 greatest care and study as to soil and natural growth have been 

 considered. 



CONCLUSIONS. 



Generally speaking, as referred to before, all the species 

 under discussion are found both on sandy and clay soil, con- 

 sequently the soil conditions need not be considered as to the 

 life of the tree. If we examine the vegetation mentioned on the 

 Alluvial Formation more closely we will find that, following the 

 shores of Lake Michigan from the north on the eastern border 

 toward the head of the lake, the specimens become smaller in 



