REGION AT HEAD OF LAKE MICHIGAN. 147 



all of which are indigenous on the Alluvial Formation, but less 

 vigorous and of smaller growth there. 



On the Glacial Drift (Prairie) as mentioned before, the 

 present vegetation has been introduced. Perhaps a lonely Cot- 

 tonwood might have made its home in suitable situations on 

 these plains, as we still find them to-day seeding themselves 

 along ditches and roadways ; still it is problematical whether the 

 young sapling would have been able to withstand the annual fires 

 that with great fury passed over these flat lands. 



Of course, groves of trees and shrubbery vegetation origi- 

 nally existed along the blufifs of the Chicago River, but these 

 have long ago disappeared with the exception of those along the 

 north fork of the Chicago River, most of which passes through 

 the Morain Formation. 



Referring to the second group : those species introduced to 

 the Morain from the Alluvial Deposit will first receive attention. 

 To my knowledge the tulip tree (Liriodendron Tulipifera) has 

 been planted as far north as Waukegan, which is about thirty- 

 five miles from Chicago. Sassafras and Nyssa multiflora have 

 also been introduced, but no species of any size worth mention- 

 ing exists outside of its natural distribution. 



Some healthy species of the tulip tree are found within a 

 short distance of Lake Michigan, and especially noteworthy are 

 the two remaining trees in the cemetery in the city of Waukegan. 

 planted by the late Robert Douglas about forty years ago. The 

 sister specimen of these trees once decorated the beautiful 

 grounds of Mr. Douglas, but was winter-killed in the winter of 

 1898 and 1899. One large specimen of sassafras, more than 

 twelve inches in diameter, is found directly at the foot of an old 

 lake beach where the Alluvial Formation and the Morain join 

 north of the city of Chicago. As this tree stands in a private 

 garden it is evident that it was planted perhaps between thirty 

 and forty years ago ; but native specimens are still found in this 

 district, yet nowhere over ten to fifteen feet high, and this size 

 very sparsely. The tree referred to is protected toward the 

 north and west by the bluflf and a group of conifers. 



Nyssa multiflora is not found in well-developed specimens 

 outside of the Alluvial Deposit; a few specimens have been re- 



