DESCRIPTIONS OF SPECIES. 57 



This is perhaps only a variety of S. Meekii, which it resembles in its 

 nervation, as far as can be observed in specimens fossilized in sandstone, 

 but, although much narrower in its general form, it is less acuminate at 

 either extremity, and is apparently sessile. As in some of our living 

 narrow-leaved willows, these leaves are generally somewhat flexuous, and 

 as they are seen lying in their natural curves on the surfaces of the rock 

 they have as familiar and perfectly willowlike a look as leaves of Salix 

 angustifolia would if artificially fossilized in the manner followed by 

 Goeppert. 



Since the above description was written I have collected this species 

 from a number of widely separated localities and found it to hold its char- 

 acter with great constancy. 



Formation and locality : Cretaceous (Dakota group). Big Sioux River, 

 Blackbird Hill, Cedar Spring, etc., Nebraska, and Whetstone Creek, New 

 Mexico. 



Salix folio sa Newb. n. sp. 



PL XIII, figs. 5, 6. 



Leaves long-petioled, broadly linear; 8 to 9 inches long by 1 inch 

 wide; suddenly narrowed to the base; acute at the summit; margins 

 entire, sometimes undulate; nervation delicate. 



Leaves of this species occur in great abundance on the banks of 

 Whetstone Creek in northeastern New Mexico, and characteristic figures 

 are given of specimens collected by myself in that locality. The leaves 

 are larger than those of any other known Cretaceous Salix, unless it be S. 

 membranacea; but it differs from that in its leaves being wedge-shaped 

 instead of rounded at the base. 



From the locality referred to, where the fossils are contained in a fine- 

 grained, light-colored sandstone, in which the most delicate tissues would 

 be preserved, we may expect the fruit of these and other fossil plants to be 

 discovered, with a decided illumination of the botanical affinities of the 

 plants of the Dakota group. 



Formation and locality: Cretaceous (Dakota group). Whetstone Creek, 



New Mexico. 



