THE FLORA OF THE SAINT EUGENE SILTS 



401 



quereux^" from the Miocene of California; and F. sylvatica 

 fossilis Laurent and Marty,-'^ from the Pliocene of the Nether- 

 lands, etc. 



In general it may be said that the specimens from the Saint 

 Eugene silts are most nearly comparable in size with leaves of 

 Fagus of recognized Miocene and Pliocene age, and that in other 

 surficial features they are closelj^ similar to the existing F. 

 grandifolia. Satisfactory dilferentiation of the several species, 

 fossil and living, one from another, is often difficult to accom- 

 plish and must, in many instances, be regarded as merely a mat- 

 ter of individual and personal opinion. As an index fossil, in 

 connection with critical stratigraphic work, it is evident that any 

 fossil leaf of this general type would be of as little value as the 

 leaves of Alnus discussed in the preceding pages. 



In our existing flora the only species native to North America 

 is F. grandifolia, and this species does not now extend further 

 north than southern Ontario or further west than Wisconsin. 



Fagus sp. 



Plate 30, figure 4 



"Fagus n. sp.?" Hollick, Summary Kept. {loc. cit.), p. 134. 



Leaf apparently about 6 to 7 centimeters in length by about 

 4 to 4.5 centimeters in maximum width ; margin dentate ; nerva- 

 tion simply pinnate ; lower secondary nerves curved and more or 

 less reflexed or bent downward toward their extremities. 



This specimen is too fragmentary for accurate or satisfactory 

 comparison ; but there can be hardly any question that it repre- 

 sents a species of beech, and it is possible that it may be only a 

 small form of the species last described. The size of the leaf, 

 in its entirety, was apparently about equal to that of the average 

 of leaves on a tree of our existing Fagus grandifolia Ehrhart, or 

 of the Old World F. sylvatica Linnaeus. In view of the frag- 

 mentary nature of the specimen, however, any further discus- 



20 Lesquereux, Leo. Mus. Comp. Zool. Harvard Coll., Mem. vol. 6, No. 2 

 (Report on the fossil plants of the auriferous gravel deposits of the Sierra Nevada), 

 pi. 2, fig. 13. 1898 (=F. Antipofii). 



21 Laurent, Louis, & Marty, Pierre. Flore foliaire Pliocene des argiles de Eeuver. 

 Rijks Geol. Dienst [Holland], Mededeel., ser. B, no. 1, p. 35, pi. 11, figs. 1-7. 1923. 



