196 



glacial bogs, is well written and the author gives frequent ac- 

 knowledgment to the excellent work of Transeau on this in- 

 teresting problem. 



In the third and longest chapter (pp. 203-311) of this part, 

 the post-glacial and recent history of the North American flora 

 is traced with some detail. That this part of the work, dealing 

 with the forces that finally shaped our present condition of things 

 fioristic, should contain even a few errors or omissions is un- 

 fortunate. Attention should especially be called to the fact that 

 south of the terminal moraine on Long Island the region is 

 mostly Tertiary, and even more modern in formation, and not 

 Cretaceous.* 



In the consideration of the strand flora of New Jersey, which 

 Dr. Harshberger has studied in some detail, he makes the state- 

 ment that Hibiscus moscheutos followed the shore line of the 

 old Penausken Sound, and that this circumstance explains the 

 occurrence of this maritime plant in the middle of New Jersey. 

 The explanation is ingenious enough, but it does not easily over- 

 come the fact that near Spotswood, N. J., which is almost 

 directly in the middle of the bed of Penausken Sound, the plant 

 is thoroughly established.! 



Lack of space forbids mention of many things discussed in 

 this part of the work, although they are of surpassing interest 

 to the phytogeographer and ecologist. It is enough to say that 

 the writer takes up each section of the continent, and gives what 

 he considers to have been the final adjustments of the flora to 

 its environment, and tells us what, to him, have been the under- 

 lying factors in the development of the ultimate fioristic char- 

 acteristics of the country. 



Such minor inaccuracies as the statement (pp. 276 and 621) 

 that Crossosoma is confined, for the most part, to the Californian 

 islands, when really there are at least two other species on the 



*This error occurs throughout the work. See pp. 218 and 421. According to 

 geological survey maps, the only outcroppings of Cretaceous on Long Island are 

 a few small ones on the north shore, near the western end of the island. 



t Dr. Harshberger makes no mention of the interesting and suggestive observa- 

 tions of Harper on the relation between the flora of the glaciated and unglaciated 

 region along the Atlantic coast. 



