DESCRIPTIONS OF SPECIES. 61 



Corylus MacQuarrii (Forbes) Heer. 

 PI. XXXII, fig. 5; XL VIII, fig. i. 



Alnites ? MacQuarrii Forbes. Quart. Journ. Geol. Soc. London, Vol. VII (1851), p. 



103, PI. IV, fig. 3. 

 Corylus MacQuarrii Heer. Urwelt. d. Sclrw. (1865), p. 321. 

 Corylus grcmdifolia Newb. Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 59; 



Ills. Cret. and Tert. PI. (1878), PL XV, fig. 5. 



"Leaves large (5 to 6 inches long), short-petioled, unequally cordate 

 at the base, pointed above, coarsely and unequally dentate; nervation 

 strong; midrib straight or curved, not sinuous; lateral nerves, six to seven 

 pairs; lower pair diverging at a larger angle than the upper ones, and sup- 

 porting a number of short, generally simple, branches, on the lower side, 

 which terminate in the basal margin; second pair diverging at an angle 

 of 45 degrees, reaching the margin about the middle, supporting about four 

 branches on the outside; upper pair simple or branched once, rarely twice." 



Collected by Dr. F. V. Hayden. 



This was evidently a large, thick, roughish leaf, having more the aspect 

 and texture of the leaves of the mulberry than of the hazel. The nervation 

 is, however, much nearer that of the latter genus. Indeed, in all essential 

 characters it is the same as that of the three species of Corylus with which 

 it is associated. The dentation of the margin, also, is acute, unequal, 

 partially double, much more like that of the leaves of Corylus than of any 

 of those with which I have compared it. 



As is remarked in the description of C. orbiculata, a large amount of 

 material has been collected and described since the description of C. grcmdi- 

 folia was written, and it has been shown that numerous leaves of Corylus 

 of large size occur in the Tertiary beds of many parts of North America 

 and extend to the European continent. Comparing our specimens with 

 these figures and descriptions, we are led to believe that our C. grandifolia 

 is only a large and strong form of C. MacQuarrii. 



Formation and locality: Tertiary (Fort Union group). Fort Union, 

 Dakota. 



