AMERICAN GEOLOGY — THE TACONIC QUESTION. 671 



tives, being quartzite in one part and mica-schist or even gneiss else- 

 where, and hence that purely lithological evidence as to the identity 

 of beds was practically worthless. This is ;i little amusing as coming 

 from Dana, who himself accepted the presence of the mineral chondro- 

 dite in the limestones of Berkshire as evidence of the Archean age. 



In 1878, T. Nelson Dale found hrachiopods belonging to the Hudson 

 River group in the Taconic slates at Poughkeepsie. In this same year 

 W. B. Dwight began work in the " Sparry limestone " of Dutchess 

 County, New York, finding fossils of undoubted Lower Silurian age." 

 These finds and others made by S. W. Ford and I. P. Bishop in 

 adjacent localities were made use of by Professor Dana in his subse- 

 quent papers. 



Dana continued in the field at intervals until 18S<:>, accepting as his 

 working basis the ('hazy fossils found by Doctor Wing at West Rut- 

 land, and accompanying and working conjointly with Wing throughout 

 the period. In 1879 he showed on stratigraphic and fossiliferous 

 evidence that the Taconic schists, so called, as developed in Dutchess 

 and adjacent counties, were of the age of the Hudson River group, 

 and the five limestone belts there found, but five successive outcrop- 

 pings of the Lower Silurian limestone brought to the surface by a 

 series of flexures. In this he agreed in the main with Mather. 



In 1884, Hall for the first time put himself fully on record as opposed 

 to the Taconic system on stratigraphic as well as paleontological 

 grounds. In this year he sent Dana copies of two sections of the 

 Taconic area and manuscript notes claimed by him to have been made 

 prior to 1845, and which gave the result of his own studies. In these 

 Mounts Anthony and Equinox art 1 shown to have a synclinal structure, 

 the limestone underlying a broad synclinal of slates and schists, the 

 former being put down as Trenton and lower, while the slates and 

 schists were of Hudson River age. Prompt publication would have 

 given Hall priority over the Vermont survey and others, but owing 

 to the long delay the matter is of only historical interest. 



In Volumes XXIX and XXXlll (1885 and 18ST)of the American Jour- 

 nal of Science. Dana again takes up the subject systematically under the 

 caption of Taconic Rocks and Stratigraphy, the paper being accom- 

 panied by a map of the region and numerous sections. He showed 

 that the flexures throughout the Taconic area were of a prevailing- 

 synclinal habit; that the limestone was a continuous formation lying 

 underneath the mountains and was overlaid conformably by strata of 

 quartzite and quartzitic and ordinary mica schist, and underlaid along 

 the eastern border by quartzite and mica schist also. He further 

 showed that within the Taconic region the texture and mineral nature 

 of the limestone beds varied geographically, the crystalline texture 

 being coarser to the southward and eastward. He found no evidence 



'Dwight later found Cambrian fossils in these same rocks. 



