44 UNITED STATES GEOLOGICAL SURVEY— TERTIARY I'LtJEA. 



wo do not find in the lignite coal any identifiable remains of the plants. It is 

 only when these hard species of Mosses are casually deposited in imid or 

 clay, or buried into sand-banks, that their forms are preserved for an indefi- 

 nite length of time. The species described below appear to have been 

 imbedded in that way along the muddy borders of a shallow lake. Of the 

 European fossil species, all those referable to the division of the Acrocarpi 

 have been found in the Succin by Gocppert; the others, all Plnurocarjd, 

 especially referable to the genus Hypnwn, have been discovered in layers of 

 clay or in beds of sandy shale. 



HYPNTJM, Linn. 



Hyp II 11 III II ay den 11, Lesqz 



Plate V, Figs. 14-14 b. 



Hypnum, Haydenii, Lesqx., Annual Report, 1874, p. 309. 



Stem rigid, sparingly divided in nearly opposite, snbalternate, short branches, slightly inflated 

 toward the top, or club-shaped ; leaves closely imbricated all around the stem and branches, ovate- 

 lanceolate, acuminate, concaye. 



The specimen is figured as far as it is discernible. The fragment 

 resembles a branch of a coarse species of Hijpnum, like H. rugosum, H. Boscii, 

 especially, a spe^es which has its largest branches divided as in this fossil 

 Moss, and of equal size. The mode of division of this plant separates it from 

 the Lycopods, while the apparently thick leaves seem abnormal for a species 

 of Moss. It is well to remark, however, that the matrix wherein the fragment 

 is preserved is a hardened plastic clay, of very fine te.xture, where even deli- 

 cate small feathers, wings of insects, etc., are distinctly recognized, and that, 

 therefore, the form of the leaves of a hard species of Moss, even their convexity, 

 may have been easily impressed upon that kind of soft sulistance. No trace 

 of middle vein is visible, of course, for the species of Hypnum have rarely 

 the nerve prominent enough upon the back of the leaves to leave an impression 

 by compression and fossilization. The point is very acute and apparently 

 piliferous, but this last character is not positively ascertained. 



Habitat. — South Park, Colorado, near Castello's Ranch {Dr. F. V. 

 Hay den). 



LYCOPODIACEiE. 



Species of this family represent an inijxirtaiit j)art of the vegetation of the 

 old coal-measures, not only by large trees, Lep'ulodendron, Ulodendron, and other 

 allied genera, but by tru(; species oi' Se/aginella and Lycopodium, known by tlieir 



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