30 LOWER AND UPPER SILURIAN FORMATIONS: 



pied in the time of the Romans by a people called the Silures. 

 It is in reality developed much more extensively in Scandi- 

 navia and Russia, as well as other parts of the world. With 

 us it- is a series of clayey and arenaceous beds, of hard con- 

 sistence ; but the characters are different in other countries. 



And what were the vessels of the mystery of life upon our 

 earth in the era of the Silurian formation, as far as these 

 rocks can inform us ? 



One would imagine that, if our present amount of geolo- 

 gical knowledge had come to us by some sudden revelation, 

 it would have been with a kind of awe that its first recipients 

 would have waited for this portion of it. But had they done 

 so, they would quickly have had to admit that nature is 

 simpler than man's wit would make her, for, behold, the in- 

 terrogation only brings before us the unpretending forms of 

 a few humble sea-plants, certain zoophytes and polypiaria, 

 and a variety of shelled marine animals ! 



To descend to particulars Fucoids, or markings produced 

 by fuci, a tribe of sea-plants, appear in the Lower Silurians 

 of Russia, below any ascertained animal remains, thus sup- 

 porting the obvious conclusion that vegetation must have 

 started fully as early as animal life, since the one thing is 

 necessary to the support of the other. In America, the same 

 vegetable remains are presented in the very first ascertained 

 fossiliferous strata ; but in England they are not as yet found 

 quite so early. In the Lower Silurians of Sweden, not only 

 are there distinct impressions of such plants, but Professor 

 Forchhammer speaks of courses of true coal, composed, as he 

 thinks, of sea-weed, and gives an opinion that the alum-slate 

 of that country owes its combustible character to the carbon, 

 sulphur, and potash, derived from marine vegetation. ( 15 ) 



Of the animals, the first we are called upon to notice are 

 Polypiaria, the creatures to which we are indebted for those 

 vast coral reefs by which the course of the mariner is so often 

 obstructed in tropical seas, beings thus productive of great 

 results, and yet in themselves extremely humble, as is partly 

 indicated by the composite form in which they exist. Next 

 to them may be ranked certain humble animals (graptolites) 



