EXPLANATIONS. 



w A geologist," he says, " whose observations had been 

 confined to Swizerland, might imagine that the coal meas- 

 Hl ures were the most ancient of the fossiliferous series. 

 When he extended his investigations to Scotland, he might 

 modify his views so far as to suppose that the Old Red 

 Sandstone marked the beginning of the rocks charged 

 with organic remains. He might, indeed, after a search 

 of many years, admit that here and there some few and 

 faint traces of fossils had been found in still older slates 

 in Scotland; but he might naturally conclude that all 

 pre-existing fossiliferous formations must be very insignifi- 

 cant, since no pebbles containing organic remains have 

 yet been detected in the conglomerates of the Old Red 

 Sandstone. Great would be the surprise of such a theo- 

 rist when he learned that in other parts of Europe, and still 

 more particularly in North America, a great succession 

 of antecedent strata had been discovered, capable, accord* 

 ing to some of the ablest palaeontologists, of constituting 

 no less than three independent groups, each of them as 

 important as the * Old Red' or Devonian system, and as 

 distinguishable from each other by their organic remains. 

 Yet it would be consistent with methods of generaliz- 

 ing not uncommon on such subjects, if he still took for 

 granted that in the lowest of these ' Transition' or Silurian 

 rocks he had at length arrived at the much-wished-for ter- 

 mination of the fossiliferous series, and that Nature had be- 

 gun her work precisely at the point where his retrospect 

 happened then to terminate."* 



It is exactly to such theorizers as the Edinburgh review- 

 er that his rebuke is applicable. When he asserts the 

 contemporaneousness of the highest mollusks with the 

 origin of organic life, he says — " We are describing pheno- 

 mena that we have seen. We have spent years of active 

 life among these ancient strata — looking for (and we might 

 say longing for) some arrangement of the ancient fossils 

 which might fall in with our preconceived notions of a 

 natural ascending scale. But we looked in vain, and we 

 were weak enough to bow to nature." The weakness 

 consisted in looking only in one little portion of the earth, 

 and believing it to be a criterion for all the rest. This 

 writer seems yet to have to learn that knowledge is to be 

 acquired by communication as well as examination. Were 

 a philosopher (supposing there could be such a being) to 

 * Travels in North America, ii., 131. 



