674 REPORT OF NATIONAL MUSEUM, 1904. 



JVereites and other trails which Emmons regarded as typical for the 

 Taconic had not yet been stratigraphically located, while (5) the grap- 

 tolites formed part of the fauna of the Hudson terrane. 



Emmons's errors, according to Mr. Walcott, were due almost wholly 

 to his trust in lithological characters; his supposed unconformity 

 between the Taconic and Champlain systems was based primarily on 

 the similarity in lithologic characters of the Calciferous sand rock of 

 the Lower Silurian, and the Calciferous sand rock of what is now 

 known, from its fossils, to be a part of his upper Taconic; also that 

 he confused the dark shales of the Lower Silurian with those of his 

 upper Taconic and failed to recognize the obvious fact that the Cal- 

 ciferous terranes were frequently represented in geological sections by 

 a shale undistinguishable from that of the Hudson River; and that in 

 several places the Trenton limestone is replaced by shale. According 

 to T. N. Dale, Emmons was also in error in assuming that the slates 

 along the east foot of the Taconic range dipped to the east, he having 

 confused cleavage with bedding. 



Fig. 141. — Section of Bald Mountain from the south. The profile of the mountain and position of 

 the Cambrian and Lower Silurian rocks are taken from a photograph. The "Upper Taconic" = 

 Cambrian slate, sandrock and limestone are shown to the right of the fault, and c=Chazy lime- 

 stone; .r=dark shales, interbedded between eand the Calciferous sandrock, E; s=dark argillaceous 

 shales beneath the Calciferous sandrock. (After C. D. Walcott.) 



At the eighth meeting of the American Committee of the Interna- 

 tional Geological Congress, which was held in New York in April, 

 1888, the subject of the subdivision and nomenclature of the American 

 Paleozoic formations was discussed, and incidentally the matter of 

 using the name Taconic, and its limitations, if used at all,' was pretty 

 thoroughly gone over. A considerable diversity of opinion was found 

 to exist; although the committee at first reported in favor of retaining 

 the name, they were apparently subsequently led to change their views 

 upon the presentation of new evidence by Mr. Walcott. A brief sum- 

 mary of some of the views adopted is given below. 



Dana objected to the retention of the name, thinking it would be 

 regarded only as "a reminder of Emmons's blundering work — a suc- 

 cession of unstudied assumptions that brought only evil to the science." 

 S. W. Ford favored the adoption of the name Taconic for the middle 

 portion of the Cambrian, as the term was then used, or that marked by 

 the presence of the fossil Olenelhts. Hall felt that it might be well to 

 retain the name for those rocks lying below the Potsdam, while C. H. 

 Hitchcock considered the lowest Taconic as of lower Potsdam age. 



