STRATIGRAPHICAL GEOLOGY. 443 



fossils, not only of State New York but also of a large portion 

 of North America. 



Contemporaneously with the investigations in New York 

 State, the two brothers Rogers (cf. p. 304) were directing and 

 participating in the survey of Pennsylvania and Virginia. 

 There also it was found that the Palaeozoic deposits were 

 exposed over wide areas, and the stratigraphical succession was 

 determined. But Edouard de Verneuil, who travelled in North 

 America in the year 1846, was the first to institute a more 

 detailed comparison between the relations of the American 

 and the European "Transitional" formation. Verneuil drew 

 up a table of the parallel palaeontological horizons in the two 

 regions, and established a line of division between the Silurian 

 and the Devonian systems in North America. Some time 

 later, J. J. Bigsby published a very exhaustive and lucid 

 synopsis of the New York system in comparison with the 

 parallel formations of Europe (Quart. Journ. GeoL Soc., 

 1858). 



The Taconic system continued to be ignored by the leading 

 geological authorities in North America, notwithstanding that 

 Emmons published a very able book on the subject in 1844, 

 affording strong evidences of the wide extension of the 

 Taconic system in the New England States, and its independ- 

 ence of the Champlain group. In Washington County, more- 

 over, the first Taconic fossils were discovered (two Trilobite 

 species, Graptolites and Nereites), and proved to be quite 

 different from any known Palaeozoic forms. Further dis- 

 coveries of fossils followed, and these were described and 

 figured by Emmons; he also traced the Taconic system in 

 Pennsylvania, Virginia, and Georgia. But as Hall, Dana, 

 Logan, and other geologists continued obstinate in their view 

 regarding the identity of the Taconic and the Champlain 

 groups, a hot polemical discussion ensued and dragged itself 

 through the following decades. 



In the year 1860, the European authorities Barrande and 

 Marcou began to take part in this discussion among the 

 American geologists, supporting Emmons in his view that the 

 Taconic system was an independent formation containing a 

 primordial fauna. Marcou wrote a series of papers, wherein 

 he advocated that the term " Taconic System " should replace 

 the disputed name of "Cambrian System" for the primordial 

 group of rocks; that the name of Cambrian System be 



