THE ORIGIN OF LIFE 275 



we may learn that the plan of creation has been 

 progressive, that there has been an advance from the 

 kw, low, and generalized types of the primaeval 

 ocean to the more numerous, higher, and more 

 specialized types of more recent times. Secondly, 

 we learn that the lower types, when first introduced, 

 and before they were subordinated to higher forms 

 of life, existed in some of their grandest modi- 

 fications as to form and complexity, and occupied 

 very important places in the economy of the world, 

 and that in succeeding ages, when higher types were 

 replacing them they were subjected to decay and 

 degeneracy. Thirdly, we learn that while the species 

 has a limited term of existence in geological time, 

 any grand type of animal existence, like that of the 

 Foraminifera or of the Sponges, once introduced, 

 continues and finds throughout all the vicissitudes 

 of the earth some appropriate residence. Fourthly, 

 as to the mode of introduction of new types, or 

 whether such creatures as Eozoon had any direct 

 connection with the subsequent introduction of 

 mollusks, worms, or crustaceans, it is altogether 

 silent, nor can it predict anything as to the order 

 or manner of their introduction. 



Had we been permitted to visit the Laurentian 



