224 THE DAWN OF LIFE. 



still exist in the deep sea. We may say more than 

 this. To some extent the conditions of the Lauren- 

 tian period still exist in the sea^ except in so far as they 

 have been removed by the action of the Foraminifera 

 and other limestone builders. To those who can 

 realize the enormous lapse of time involved in the geo- 

 logical history of the earth, this conveys an impression 

 almost of eternity in the existence of this oldest of all 

 the families of the animal kingdom. 



We are still more deeply impressed with this when 

 we bring into view the great physical changes which 

 have occurred since the dawn of life. When we con- 

 sider that the skeletons of Eozoon contribute to form 

 the oldest hills of our continents ; that they have been 

 sealed up in solid marble, and that they are associated 

 with hard crystalline rocks contorted in the most fan- 

 tastic manner ; that these rocks have almost from the 

 beginning of geological time been undergoing waste to 

 supply the material of new formations ; that they have 

 witnessed innumerable subsidences and elevations of 

 the continents ; and that the greatest mountain chains 

 of the earth have been built up from the sea since 

 Eozoon began to exist, — we acquire a most profound 

 impression of the persistence of the lower forms of ani- 

 mal life, and know that mountains may be removed 

 and continents swept away and replaced, before the 

 least of the humble gelatinous Protozoa can finally 

 perish. Life may be a fleeting thing in the individual, 

 but as handed down through successive generations 

 of beings, and as a constant animating power in 



