THE PRIMORDIAL, OR CAMBRIAN AGE. 55 



Lingula and Nautilus, have persisted down to modern 

 times, others, like the Trilobites and Orthids, perished 

 very early. In all this we can dimly perceive a 

 fitness of living things to physical conditions, a 

 tendency to utilise each type to the limit of its capa- 

 cities for modification, and then to abandon it for 

 something higher ; a tendency of low types to appear 

 first, but to appear in their highest perfection and 

 variety; a sudden apparition of totally diverse plans 

 of structure subserving similar ends simultaneously 

 with each other, as for instance those of the Mollusk 

 and the Crustacean; the appearance of optical and 

 mechanical contrivances, as for example the compound 

 eyes of the Trilobite and the swimming float of the 

 Orthoceras, in all their perfection at first, just as they 

 continue to this day in creatures of similar grade. 

 That these and other similar things point to a uniform 

 and far-reaching plan, no rational mind can doubt; 

 and if the world had stopped short in the Primordial 

 period, and attained to no further development, this 

 would have been abundantly apparent; though it 

 shines forth more and more conspicuously in each 

 succeeding page of the stony record. How far such 

 unity and diversity can be explained by the modern 

 philosophy of a necessary and material evolution out of 

 mere death and physical forces, and how far it requires 

 the intervention of a Creative mind, are questions 

 which we may well leave with the thoughtful reader, 

 till we have traced this history somewhat further. 



