No. 385.] REVIEWS OF RECENT LITERATURE. 27 
factory manner. Both the botanist and geologist will find his work 
of the greatest value — quite indispensable, indeed, in a study of the 
fossil flora of the earth. 
The rich collections of the British Museum, as well as other great 
collections in Britain and elsewhere, have furnished the author with 
a great mass of valuable materials, of which he has made most excel- 
lent use. aes 
The first three chapters of the present volume comprise, first, a 
comprehensive sketch of the development of the science of paleo- 
botany; a chapter on the relation of paleobotany to botany and 
geology; and an extremely clear account of the succession and limits 
of the principal geological periods. A most interesting chapter 
follows, dealing in a striking way with the factors concerned in the 
preservation of plant remains. As plants are for the most part 
destitute of skeletal tissues, except wood, it is not surprising that 
they have left relatively few remains when compared with animals. 
This is especially the case among the lower non-vascular plants. 
Many interesting illustrations are given to show how the process of 
fossilization is going on at the present day. One of the most strik- 
ing is the description of the great masses, or rafts of vegetation, 
drifted out to sea from the mouths of large rivers, like the Missis- 
sippi or Amazon. The harder and less perishable structures, like 
the trunks of trees, and hard seeds or fruits, finally sink to the 
bottom of the sea, often hundreds of miles away from their original 
habitat, and, gradually buried in the sediment at the bottom, may in 
future ages appear as fossils, mingled with various marine forms. It 
is probable that the occurrence of terrestrial, or fresh-water organ- 
isms in fossil beds of marine origin is to be accounted for in this 
manner. 
It is rather startling to learn that not only may such structures as 
the cuticle and cell walls of the epidermis be preserved, but that 
delicate parenchyma cells with traces of the contained protoplasm 
and nuclei can occasionally be recognized in a fossil condition! The 
most perfect fossils are those in which there has been an infiltration of 
silicious matter, and such petrifactions often have the tissues so per- 
fectly preserved that microscopic sections reveal most beautifully the 
details of the cellular structure. It is the study of such sections 
that has done more, perhaps, than anything else to explain the real 
affinities of the plants in question. ee 
Chapter V deals with the difficulties and sources of error encoun- 
tered in dealing with fossil plant remains, and shows how cautious 
