REPORT OF THE STATE PALEONTOLOGIST 1901 639 



sidence, whose earliest effects, so far as marine deposition is con- 

 cerned, are seen in the Chazy limestone of the northeast and the inv^sk)"^^"^ 

 lower Stones river formations of Tennessee and Kentucky. In 

 the latter regions the subsidence continued, without serious in- 

 terruption, to the close of the Black river, when elevation, result- 

 ing in the first emergence and subsequent erosion of the Cin- 

 cinnati and Nashville domes or pmina of Suess, took place. In 

 the meantime, the Mississippian sea, which seems to have 

 entered from the south, was steadily advancing northeastward, 

 reaching the Mohawk and St Lawrence valleys, as we shall have 

 occasion to explain more fully, just before the close of the Stones 

 river age. 



With the earlier part of this subsidence, the Atlantic invaded 

 the continent westward by means of the two subparallel and 

 closely approximated channels that we have called the Chazy J^n^^jjba' 

 bay and the Levis channel. The former extended along the 

 northwestern side of the Quebec barrier, which separated the 

 two channels, up the St Lawrence to the northeast angle of the 

 Adirondack mass, where it divided, one arm entering the Ottawa 

 basin, the other passing on up the Champlain valley to or about 

 Westhaven. The typical Chazy formation, which represents the 

 deposits of this bay, bears evidence in its members of having 

 encroached southward and. westward in the arms, the latest beds, 

 except where, apparently, they were removed before being 

 covered by the next formation, extending farthest south and^ 

 west. 



The Levis channel, which occupied the narrow trough between Levis channel 

 the Quebec and Green mountains barriers, extended from New- 

 foundland southw^estward as far at least as Kensselaer county, 

 N. Y., where Ruedemann has found the typical Levis fauna. Its 

 deposits consist almost wholly of shales, with occasional rather 

 local thin bands of impure limestone and accumulations of con- 

 glomerates, as at Levis opposite Quebec city. The faunas, which 

 in their general aspect are decidedly European, consist mainly 

 of graptolites, that of the Levis formation being particularly 

 characterized by several species of Phyllograptus. The respec- 



