272 
Charles Schuchert. 
THE EVOLUTION OF PRIMITIVE PLANTS FROM 
THE GEOLOGIST’S VIEWPOINT. 
By Charles Schuchert. 
HE writer has read with a great deal of profit A. H. Church’s 
recent valuable memoir, “ ThaJassiophyta and the Subaerial 
Transmigration” 1 and A.G.T.’s clear and searching review of it, 
“ The Evolution of Plants.” 2 Church’s paper is of great importance 
not only to all botanists, but to all teachers of Historical Geology 
as well, and the writer, as a member of the latter group, is thankful 
to him for having written it. As paleontologists we may accept his 
conclusions and leave to the botanists the discussion as to the 
course of evolution the marine algae took in their ascent to land 
plants. As a paleontologist and geologist, however, the writer 
cannot accept some of Church’s geologic dicta, and since the 
editor of the New Phytologist invites criticism, the following 
questions may be raised. 
First, did the earth ever have a universal ocean ? Second, has 
the amount of water in the hydrosphere decreased or increased 
during the geological ages ? Third, was the primal ocean as salty 
as it is to-day, and what is the source of these salts? 
The answers to these questions must be sought in the light of 
what is going on in the world about us and of what the astronomers, 
geophysicists, and geologists tell us about the evolution of the galaxy 
and of the constellation of the sun, and the origin of the earth. 
The famous Laplacian theory of earth origin, adapted by the elder 
Dana to the earliest stages of earth evolution, is now badly 
shattered, and out of it has risen a new one, the Chamberlin- 
Moulton planetesimal hypothesis. In accordance with this later 
theory, the earth never was a star that finally became encrusted 
with a rocky surface, above which floated an atmosphere holding 
all the water now on the earth’s exterior and that which has 
percolated to the exterior portion of the lithosphere during the 
geologic ages. The universal ocean of the ancients, fastened upon 
geology more than a century ago by Werner, was a figment of his 
imagination. On the contrary, the earth’s oldest surface, probably 
never to be discovered, was composed of far more dry land than 
water. Ocean basins in the sense of those of to-day may then not 
have existed. All of the water on the face of the earth has been 
1 Oxford Botanical Memoirs 3 , 1919. Oxford Univ. Press. Price 3s. 6d, 
a New Phyt. 19 , 1920, p. 1 . 
