AND THE REPORT ON THE GEOLOGY OF VERMONT. 



131 



TABLE B. 



SHOWING THE VARIOUS GRAPTOMTIC ZONES, GEOLOGICAL AGE AND CLASSIFICATION FOR THE 

 NORTHEASTERN PART OF NORTH AMERICA, BY JULES MARCOU, 1887. 



The fourth zone of Graptolites is older than any of the zones of Professor Lap worth ; 

 and although containing onl}^ three species, found at Parker's quarry (Georgia) and at 

 Porter's Brook, St. Martin, near St. John (New Brunswick), is most important, for it 

 shows, without a possible doubt, that the Graptolites made their api^earance in America 

 sooner than in Europe (England, Scandinavia and Bohemia). 



There is a great gap between the second and first graptolitic zones, during the de- 

 posit of the Potsdam, Calciferous, Chazy, Birdseye, Black river and Trenton. In America 

 the Graptolites belong mainly to the Middle and Upper Taconic, or primordial and supra- 

 prunordial faunas. 



