Chapter 22 



FOSSIL FUNGI 



At first thought fossil fungi might be regarded as outside the 

 field of interest of the student of fungi and of little, if anv, innate 

 value to him. It must be admitted that in the past few contribu- 

 tions to our knowledge of fossil fungi have been made by mycolo- 

 gists. This field of inquiry has been left to geologists, whose 

 knowledge of fungi, it is to be hoped, exceeds the mycologists' 

 acquaintance with geology. There are doubtless few mycologists 

 who have ever seen any fossil fungi, and until an occasional worker 

 comes to have some first-hand knowledge of them, there can be 

 no lively interest in objects so long dead and buried. The reason 

 for discussing fossil fungi in this work is that a better acquaintance 

 with the geological history of fungi will, it is hoped, contribute to 

 a greater appreciation of the present place of these plants in the 

 economy cf nature. 



GEOLOGICAL TIME 



Rocks have been truly said to constitute the documentary 

 source books of geological history 7 . By using the evidence ex- 

 hibited by rocks, that is, their kind, their composition, their posi- 

 tion, and their content of minerals and fossils, geologists are able 

 to interpret the past developmental history of the earth and to 



forecast the future. In so doing they denote segments of geologi- 

 es O C 1 o 



cal time as eras, periods, epochs, and stages, which in point of view 

 of time are not sharply delimited one from the other. If, since 

 the beginning of geological time, there had not been inequalities 

 in the amount of heat received from the sun by different regions 

 of the earth's surface, and if rock formation had everywhere pro- 

 ceeded uniformly and without interruption, a geologist could 

 examine a vertical section of the earth's crust anywhere, and the 

 whole monotonous course of events would be in evidence. Cli- 



414 



