126 



LAKAMIE FLOKA OF THE DENVER BASIN. 



Populus? distorta Knowlton, n. sp. 



Plate IV, figure 6. 



Populus? distorta Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 488, 1919. 



Leaf of small size, unequal sided, probably 

 more or less distorted or malformed, outline 

 now broadly ovate, possibly nearly circular 

 when perfect, base abruptly rounded and 

 truncate, apex obtusely acuminate; three- 

 ribbed from the extreme base of the blade, 

 midrib with about two pairs of thin secondary 

 branches high up above the middle, lateral 

 much arched outward, each with several thin 

 branches on the outside. 



This form is represented by the single ex- 

 ample figured, and this seems not to be normal 

 in that it was probably nearly circular in out- 

 line when perfect, though now it is distinctly 

 narrowed on one side. The length is 4.5 centi- 

 meters and the width about 3 centimeters, 

 though if the supposition of its abnormality 

 is correct it should have been a little over 4 

 centimeters in width. 



This appears to be a poplar of the type of 

 Populus arctica Heer n — that is, on the sup- 

 position that one side has become reduced, 

 probably by injury or pressure — but as it may 

 be normal the reference to Populus has been 

 questioned. 



Occurrence : Laramie formation, Cowan sta- 

 tion, 10 miles south of Denver, Colo., collected 

 by F. H. Knowlton. ^ 



Order FAGALES. 



Family FAGACEAE. 



Quercus praeangustiloba Knowlton, 



, Plate V, figures 6, 7 (types). 



Quercus praeangustiloba Knowlton, U. S. Geol. Survey 

 Bull. 696, p. 535, 1919. 



Quercus angustiloba Al. Braun. Lesquereux, IT. S. Geol 

 and Geog. Survey Terr. Ann. Rept. for 1872, p. 378 

 1873; idem for 1873, p. 381, 1874; idem for 1876, p 

 506, 1878; Tertiary flora: U. S. Geol. Survey Terr 

 Rept., vol. 7, p. 161, pi. 21, figs. 4, 5, 1878. [Lea 

 quereux's original figures of these types are here 

 reproduced.] 



The two specimens upon which this species 

 is based, and apparently the only ones ever 

 obtained, are in the collections of the United 

 States National Museum (Nos. 191, 192). 



il Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. 

 Rept., vol. 7, pi. 23, figs. 1-5, 1878. 



They are preserved on the white fine-grained 

 sandstone characteristic of the Laramie at 

 Golden, Colo., and are rather obscure, though 

 the figures given by Lesquereux and here 

 reproduced show them very well. 



These leaves have until now been referred to 

 the European Quercus angustiloba Al. Braun, 72 

 but as that species occurs in the Olig'ocene it 

 seems inherently improbable that it should be 

 common also to the American Upper Creta- 

 ceous, though of course this is not in itself 

 proof that they are not the same. In the 

 matter of outline they are certainly very simi- 

 lar, but the nervation is. obscurely retained in 

 the European specimens, and until material is 

 obtained showing them to be identical it seems 

 best to treat them as distinct. 



These American leaves have a rather strong 

 resemblance to certain leaves of Artocarpus. 

 In" both the leaves under consideration, the 

 strong secondaries next above the ones going 

 to the lower lobes pass directly toward the 

 sinuses, but it is impossible to see whether they 

 enter the margin or pass around the sinus as 

 intramarginal veins. In one of the larger lobes ■ 

 there seems to be an intramarginal vein, as in 

 Artocarpus, but it is too indistinct to be made 

 the basis for transferring them to that genus. 



The specimen from Campbell's quarry, Cross 

 Lakes, La., referred by Lesquereux n to Quercus 

 angustiloba, is also in the United States National 

 Museum (No. 2551). It proves to be a minute 

 fragment without base, apex, or perfect sides 

 and is absolutely worthless in determining the 

 presence of this or any other species. 



Occurrence: Laramie formation, Golden, 

 Colo. 



Quercus straminea Lesquereux. 



Quercus straminea Lesquereux, U. S. Geol. and Geog. 

 Survey Terr. Ann. Rept. for 1872, p. 373, 1873; 

 Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 

 7, p. 151, pi. 19, .figs 6, 7, 1878. 



The type specimens of this species are pre- 

 served in the United States National Museum 

 (fig. 6 = No. 173, fig. 7=No. 174) and are on the 

 hard sandstone matrix of the Laramie. These 

 two specimens are so unlike that it was at one 

 time thought best, to separate them; in fact, 

 Lesquereux himself has called attention to 

 this difference. On this point he says: 



« Braun, Al., in Ludwig, Rudolph, Paleontographica, vol. 8, p. 103, 

 pi. 36, fig. 3, 1860. 

 ™ U. S. Nat. Mus. Proc, vol. 11, p. 25, 1888. 



