64 RounD: A MODERN PLANT FossIL 
of fossils.* Given, however, materials of as tough a nature 
as the shelf fungus from the hemlock stump, on which a leaf 
had been encrusted or replaced by hyphae of the same tough- 
% 
Fic. 1. Black birch leaves “fossilized” on a_ shelf fungus, X 3%. Original 
specimen now in the Paleontological Laboratory, Brown University. 
ness, one has but to postulate the submergence of the fungus 
in the surrounding peat bog and conditions are supposedly right 
for its continued preservation.+ 
It appears, therefore, that the fungus above described with 
its encrusted black birch leaves illustrates a method whereby 
fossils may have formed in the past or may develop under mod- 
ern conditions. It may therefore be popularly designated as 
exemplifying a ‘‘modern plant fossil.’ 
* Pirsson & Schuchert, Text book of geology, p. 435, 1915. 
Tt See Shimer, An introduction to the study of fossils, p. 3, 1918. 
