No. 3.] HUNT — ON CAMBRIAN AND SILURIAN. 305 



same time, rccoirnized this as distinct from and older than the 

 second fauna, discovered in theLhindeilo rocks, which Murchison 

 had dcchired to represent the dawn of organic life. Into the 

 reasons which led Barrande to include the rocks of the first, 

 second and third faunas in one Silurian system, (a view which 

 was at once adopted by the British Geological Survey and by 

 Murchison himself.) it is not our province to inquire, but we 

 desire to call attention to the fact that the latter, by his own 

 principles, was bound to reject such a classification. In his address 

 before the Geological Society in 1842, (already quoted in the first 

 part of this paper,) he declared that the discussion as to the value 

 of the term Cambrian involved the question "whether there was 

 any type of fossils in the mass of the Cambrian rocks diff"erent 

 from those of the Lower Silurian series. If the appeal to nature 

 should be answered in the negative, then it was clear that the 

 Lower Silurian type mut^t be considered the true base of what 

 I had named the protozoic rocks ; but if characteristic new forms 

 were discovered, then would the Cambrian rocks, whose place was 

 so well est:iblished in the dcf-cending series, have also their own 

 fauna, and the paleozoic base would necessarily be removed to a 

 lower horizon." 



In the event of no distinct fauna being found in the Cambrian 

 series, it was declared that *' the term Cambrian must cease to be 

 used in zonlogic il classification, it bt'ing, in that eense, synony- 

 mous with Lower Silurian/' [Proc. Geol. Soc. Ill, 641 et ^^eq.] 

 That such had been the result of paleontological inquiiy Mur- 

 chison then proceeded to show. Inasmuch as the only portion of 

 Sedgwick's Cambrian which was then known to be fossiliferous, 

 was re illy above and not bjlovv the LLmduilo rocks, which Mur- 

 chis^On had taken for the base of his LoVer Silurian, his reason- 

 ing with regard to the Cambrian nomenclature, based on a false 

 datum, Was itself fallacious ; and it might have been expected 

 that when the government surveyors had shown his stratigraphical 

 error, Murchison would have lendertd justice to the nonjenclature 

 of Sedgwick, But when, still later, a f..rther ";.ppe..l to nature" 

 led to the discovery of " characteristic new foims," and estab- 

 lished the existince of a " type of fossils in the mas? of the Cc.m- 

 brian rocks, different f)om those of the J^ower Siluri.m series," 

 Murchison was bound by his own principlcfi to recognize the name 

 of Cambrian for the great Fystiniog' group, with its primordial 

 Vol. VI. M No. 3. 



