Where did Life Begin f 25 



Whether this is so, and whether at the time 

 of the first advent of Hfe upon the earth, 

 southern continents now submerged were 

 drained off, and the northern continents sub- 

 merged, or whether the northern continents 

 were drained off and the southern submerged, 

 as at present, is quite immaterial for the pur- 

 poses of our inquiry. One thing is certain, 

 that with the present amount of water upon 

 the earth, to submerge the continents of the 

 northern hemisphere as deep as the floor of the 

 southern oceans, would necessarily drain off 

 vast bodies of land in the southern hemi- 

 sphere, and give the south pole a surrounding 

 zone of land such as the north pole now has. 

 Such a condition of things would keep all life 

 in a constant migration, north and south, and 

 almost from pole to pole — at any rate, from 

 one frigid zone to the other. 



Since then it makes no difference, for the 

 purposes of our inquiry, whether there have 

 been such alternate changes, and also to avoid 

 distracting the attention by looking first to 

 one pole and then to the other, we will con- 

 sider this matter as though the continents and 



