COMPOSITION OF TllK KI.OKA. 



Ill 



as shown roughly on the accompanyuig sketch 

 map (fig. 7). About 15 fossil forms have been 

 described. The oldest known, 5 Eocene species, 

 come from western North America. There are 

 2 Oligocene species in Europe and about 6 

 Miocene species in Oregon, Spitzbergen, and 

 throughout Europe. The larger number of 

 Grewia-like fossil forms are, however, referred 

 to the genus Grewiopsis of Saporta. Si.K of 

 these forms come from the Upper Cretaceous 

 and all are confined to North Amerit;a, a very 

 significant fact, since several of them are espe- 

 cially well marked. They are found in the 

 Magothy formation of the east coast, tlie Tus- 



ancestors were common in the Upper Creta- 

 ceous and Eocene of North America. 



The fourth fo.ssil genus of Tihaceie is 

 Apeibopsis Heer, named from its affinity with 

 the existing genus Apeiba Aublet, which con- 

 tains 5 or 6 species that arc confined to tropical 

 South America. To this genus should prob- 

 ably l)e referred the jVirtic forms descril)ed by 

 Heer as Nordenskioldia. Apeibopsis includes 

 not only leaves but very characteristic fruits. 

 To it are referred somewhat doubtfully deter- 

 mined leaves from the I'pper Ci'etaccous 

 Dakota sandstone and Atane beds. There are 

 al)out 14 Tertiary species, including a basal 



I''ii.i'i:r: 7 — Skt'tili inap^liinving ar**as of disl.riliuliuii uf recent and fossil species of Grewia and Grewiopsis 



species of Grewja and Grewiopsis; 2, Tertiary species of Grewia. 



1 , Cretaceous and Tertiary 



caloosa fonnation of the south coast, and the 

 Dakota, Montana, and Laramie formations of 

 the western interior region. There are about 

 6 Eocene species in the Denver, Trance, and 

 Fort Union, 1 in the Wilcox and 1 in the 

 Claiborne of the Mississippi em})ayn^ent region, 

 6 m the Paleocene of Fraiu-e, and 1 in the 

 Ypresian of England. A Miocene (?) species 

 is recorded from Yellowstone Park. This geo- 

 logic distribution is plotted on the accompany- 

 ing sketch map for comparison with the exist- 

 ing range of Grewia, and, Ihougl^ some of tlie 

 fossil records ascribed to tlie geiuis Populus are 

 possibly those of Grewia or its ancestral stock, 

 it seems clear that the Grewia or its immediate 



Eocene form from Wj'oming, 2 Ypresian forms 

 from England, a species from west Greenland, 

 3 species in the hgnites of Brandon, Vt., 2 

 Ohgocene species from Italy, and 5 Miocene spe- 

 cies from France, Switzerland, and Bohemia. 

 The family Bombacacete,' which includes 20 

 genera and about 120 existing species, is con- 

 fined to the Tropics, and principally to the 

 American Tropics. The only known fossil 

 forms are those of the genus Bond)ax or the 

 allied Bombaciphyllum and Bombacites. Bom- 

 bax Linne includes about 50 existing species, 

 all large tropical trees and almost confined to 



lEttingshauscn.C. von, Ucber die nervation dcrBombacecn: IC.Vkad. 

 Wiss. Wicn. Matll.-nat. Cl.. Denlisciir., Bd. 11. pp. 49-02. pis. 1-11, IS,')*. 



