FLOEA OF THE DAKOTA GROUP. 49 



Picas I : ( 1 1 r o 1 1 1 1 \ 1 1 a . Lesqx. 



Plate I, Figs. 12, 13. 



Hayden'a "Ann. Rep.," 1874, p. 342, pi. v, fig. 7. 



laurophyllum reticulatum, Lesqx., "U. S. Geol. Rep.," vi, p. 76, pi. xv, figs. 4, 5. 



Leaves coriaceous, polished on the upper face, entire, narrowly lanceolate, acumi- 

 nate, gradually taperiug to a short thick petiole; medial nerve thick, grooved on the 

 upper side; secondary veins close, very open. 



A large number of specimens of this fine species have been examined. 

 Though generally more or less fragmentary and often erased on the sur- 

 face, the essential characters may be generally recognized. The leaves 

 vary in size from 10 to 20 centimeters long and from li to 4£ centimeters 

 broad in the middle. They are lanceolate, gradually narrowed both ways 

 from the middle. The secondary nerves are parallel, unequal in distance, 

 nearly at right angles to the midrib, and also nearly straight in passing to 

 near the borders, where they curve and anastomose in festoons. They 

 are generally separated by one or two tertiary veins attached to them by 

 branches either oblique or at right angles, whose subdivisions compose an 

 irregularly quadrate areolation. 



By its nervation this species has a typical relation to F. Glascoena. 

 The curves of the secondary veins, which follow close to the borders in 

 successive bows, form a kind of margin, as in the preceding species; but 

 the veins distinctly curve to the festoons and compose them. They do 

 not abruptly anastomose with them by their attenuated ends; for this 

 reason the marginal flexures are thin, rarely distinct in this species, while 

 in F. Glascoena they appear as formed by a truly independent nerve, more 

 deeply and distinctly marked than the ends of the secondary veins. 



In the collection of the Museum of Comp. Zool. of Cambridge I have 

 found fourteen specimens of leaves same size and form as those described 

 here, with the same character of areolation, but with the secondary veins 

 at an acute angle of 30°. All the specimens are from the same locality, 

 Elkhorn Creek, and seem to represent a truly different species. But the 

 lateral veins and their divisions are not distinct enough to be satisfactorily 

 described. 



At first I considered the relation of these leaves to be with the 

 Laurineoe. But as remarked already in the first description of this species, 



C F 4 





"4 4 



