373 



" The great American paleontologist arrived long since at the same 

 conclusion, for in 1847 he wrote the following passage in the Introduc- 

 tion to the first volume of the Monumental Work consecrated to the 

 Paleontology of New York. 



" ' Every step in this research tends to convince us that the succession 

 of strata, when clearly shown, furnishes conclusive proofs of the existence 

 of a regular sequence among the earlier organisms. We are more and 

 more able, as we advance, to observe that the Author of nature, though 

 always working upon the same plan and producing an infinite variety 

 of forms almost incomprehensible to us, has never repeated the same 

 forms in successive creations. The various organisms called into ex- 

 istence have performed their parts in the economy of creation, have 

 lived their period and perished. This we find to be as true among the 

 simple and less conspicuous forms of the paleozoic series, as in the 

 more remarkable fauna of later periods.' — J. Hall, ' Pal. of New York,' 



Lp.XXUL" 



" When an eminent man expresses such ideas so eloquently, it is be- 

 cause they rise from his deepest convictions. It must then be conceived 

 that J. Hall, restrained by the artificial combinations of stratigraphy 

 previously adopted by him, has done violence to his paleontological doc- 

 trines, when, seeing before him the most characteristic forms of the Pri- 

 mordial fauna, and giving them names the most significant of this first 

 creation, he thinks it his duty to teach us that these three trilobites 

 belong to a horizon superior to that on which the second fauna is extin- 

 guished. 



" In eff'ect, according to the text of J. Hall, the three trilobites in ques- 

 tion were found near the town of Georgia, Vermont, in schists which are 

 superior to the true Hudson River group. In his works J. Hall does 

 not go beyond indicating the horizon of certain fossils, and no one 

 would think of asking a guaranty for such indications. But on this 

 occasion the great American paleontologist thinks it necessary to sup- 

 port his stratigraphical determination by another authority, chosen 

 from the most respectable names in geology. The following is the note 

 which terminates his Memoir. 



" ' Notp:. In addition to the evidence heretofore possessed regarding 



the position of the shales containing the Trilobites, I have the testi- 

 mony of Sir W. E. Logan, that the shales of this locality are in the 

 upper part of the Hudson Eiver group, or forming a part of a series of 

 strata which he is inclined to rank as a distinct group, above the Hud- 

 son River proper. It would be quite superfluous for me to add one 

 word in support of the opinion of the most able stratigraphical geologist 

 of the American continent.' 



" Now, when a savant like J. Hall thinks himself obliged to invoke 



