812 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



of foliage makes it impossible to correlate it any more definitely with existing 

 species, and it is therefore unwise at present to assign any specific name. 



A review of the American history of this genus shows that on the whole, 

 it has heretofore been recognized chiefly with respect to the Pleistocene forma- 

 tion, in which Penhallow (48, 49), and Dawson (6,75) have recorded a number 

 of species represented by their foliage. Knowlton (25) has similarly recorded 

 the genus as occurring in the glacial deposits of West Virginia, but in all of 

 these cases the plants found may be directly correlated with existing species. 

 Lesquereux (42, 142, pi. xxiii., f. 5 — 6) has recorded the existence of Potamoge- 

 ton in the Green Elver group at Florissant, Colorado, where two species are 

 recognized: the one, P. verticillatus, Lesq., being known by its leaves only; the 

 other, P. geniculatus, Al. Br., being known through both fruit and leaves. There 

 is, therefore, no substantial reason for questioning the character of the fruits 

 as described in the present instance. 



of 1905. Ulmus,, sp. 



o 



An undeterminable species of elm, represented by a fragment of a leaf, 

 showing nothing but venation, and probably referable to one of the woods of 

 the same genus described. 



— ^— of 1905. Betula, sp. 



This specimen embraces three fruit bodies, two of which are but imperfectly 



represented, while the third shows a perfect, oval form, 4x8 mm., with well 



defined scales. It is a small cone, representing the fruit of Betula, possibly 



* 250 

 the same as- — . On the same slab are various fragments of stems, more or 

 lc 



less carbonized. These are several centimetres long and upwards of more than a 



centimetre in width. Their character cannot be determined, but they apparently 



represent small branches of some woody exogen, possibly of Betula itself. 



— — of 1905. Taxodium distichum. 



The only representative of this genus is to be found in a portion of the 

 male inflorescence, about 4-7 cm. long. The central axis is rather stout and it 

 bears several well-defined inflorescences, together with one or two which are 

 detached. These latter show the characteristic features of the male flowers of 

 Taxodium, as already recognized by Knowlton (34), in specimens derived from 

 the Mascall Beds of the John Day Basin (IT. Miocene) of Oregon. 



CRETACEOUS. 



Leaves of Endoge^s. 



The only specimen under number 1433 showed on one side, two small frag- 

 ments of leaves which, from their obviously parallel venation, are to be regarded 



