no. 1821. REVISION OF POTOMAC PLANTS— BERRY. 307 



This form, which is of rare occurrence, is possibly not specifically 

 distinct from Brachyphyllum crassicaule Fontaine, which in turn is 

 very closely allied to various European forms. It may be distin- 

 guished, however, from the preceding species by its slender branches, 

 which rarely fork, and then in an apparently dichotomous manner 

 (this is only apparent, however, and not real dichotomy), and by its 

 more regular, pointed, slightly keeled leaves. The specimens from 

 Glen Rose, Texas, described as new by Professor Fontaine, are not 

 distinguishable from the Maryland and Virginia specimens of 

 Brachyphyllum parceramosum. 



Brachyphyllum parceramosum is retained as a distinct species 

 because of the inconclusive nature of the material and because it 

 occurs in beds of somewhat greater age than Brachyphyllum crassi- 

 caule and because in habit it more nearly resembles the less branched 

 Jurassic types rather than the more regularly and pinnateh/ branched 

 Cretaceous types, the latter type culminating in Bracliy phyllum 

 macrocarpum of the Upper Cretaceous. The great similarity among 

 all of the species in this genus when studied as poorly preserved 

 impressions tends to enforce caution on the student who would unite 

 under one name forms which appear to be similar, but which are 

 widely removed either geologically or geographically. The European 

 representative of Brachyphyllum parceramosum is Brachyphyllum 

 obesiforme elongatum Saporta, which occurs in the Albian of Portugal. 



Occurrence. — Patuxent formation: Telegraph Station (Lorton), 

 Virginia; New Reservoir, District of Columbia. Arundel forma- 

 tion: Arlington, Maryland. 



Collections. — U. S. National Museum. 



THE GENUS SEQUOIA. 



The genus Sequoia was proposed by Endlicher in 1847, 1 being based 

 upon the still existing species of the Pacific coast of North America. 

 What appears to be the earliest authentic record of a fossil Sequoia is 

 furnished by the cones collected in the Portlandian of France. 2 



Ranging through the succeeding Lower Cretaceous deposits about 

 a dozen species are known. The localities include Maryland, Vir- 

 ginia, California, Montana, Wyoming, and Texas, and outside the 

 United States British Columbia, Greenland, Mexico, Spitzbergen, 

 Portugal, Belgium, Germany, Switzerland, England, and Russia. 

 Wood of the Sequoia type of structure is also known from the Lower 

 Cretaceous of this country and Europe. In the Upper Cretaceous 

 species of Sequoia become still more abundant and they apparently 

 extend their range and specific differentiation throughout the greater 

 portion of the succeeding Tertiary period, some of the forms, repre- 



i Endlicher, Synop. Conif., 1847, p. 197. 



' Fliche and Zeiller, Bull. soc. geol. France (4), vol. 4, 1904, p. 79S, pi. 19, figs. 4, 5. 



