DESCRIPTION OF NEW FOSSIL LIVERWORT FROM THE 

 FORT UNION BEDS OF MONTANA. 



By Frank Hall Knowlton, 

 Custodian of Mesozoic Plants, U. S. National Museum. 



The Liverworts or Hepaticse in a fossil state are of such extremely 

 rare occurrence that each additional authentic instance becomes a 

 matter of exceptional interest, and it is therefore with great pleasure 

 I am able to record the presence, in the Fort Union (Eocene) beds, 

 of what seems an indisputable member of this group for which I 

 propose the name: 



MARCHANTIA PEALEI, new species. 



Thallus of large size, at least 8 cm. long and 1.25 cm. wide, dis- 

 tinctly forking and with the margins erose or erose-undulate; " mid- 

 rib " broad and diffused with the bundles of closely appressed rhi- 

 zoids radiating obliquely from it in such a manner as to simulate 

 veins; fruit not preserved. 



Type-locality. — Hedges coal mine, north side of Yellowstone River, 

 opposite Miles City, Custer County, Montana. 



Horizon. — Lower portion of Fort Union (Eocene). 



Type-specimen.— Cut. No. 33028, U.S.N.M. 



The splendid specimen, so well shown in the figure, was collected 

 by Dr. A. C. Peale and Mr. A. J. Collier in August, 1007. from ma- 

 terial excavated at a point about 8 feet above the principal coal vein 

 of the vicinity and was the only specimen of the species secured. It 

 is preserved in a soft, fine-grained grayish white clay, and as much of 

 the carbonaceous matter is still present, it exhibits the characters very 

 distinctly. It has been very little distorted and still has much the 

 appearance of one of the living species growing over the surface of 

 the ground ; in fact, it is rather difficult in the absence of fruit to find 

 characters by which to definitely separate it from the living Mar- 

 chantia polymorpka Linnteus, of such wide geographical distribu- 

 tion. As may be seen from the figure, it is very distinctly forked, one 



Proceedings U. S. National Museum, Vol. XXXV— No. 1639. 



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