356 



SCIENCE 



[N. S. Vol. XXIX. No. 739 



SlLTJEIO 



Ontaeic. 



Obdovicic 



Champlainic. 



Upper Silui-ic or 

 Monroan (900-1,000 ft.) 



Middle Siluric or 

 Salinan (1,000 ft.) 



Lower Silurie or 

 Niagaran (1,000 ft.) 



f Upper Ordovicic or 

 Trentonian ( or Cincin- 

 natian, sens, lat., or 

 Nashvillean) 

 (1,000-1,500 ft.) 



Middle Ordovicic or 

 Chazyan (2,500 ft.) 



Lower Ordovicic or 

 Beekmantovmian 

 (2,500 ft.) 



Upper Cambric or 

 Bretonian 



Middle Cambric or 

 Acadian 



Lower Cambric or 

 Etcheminian 



Georgian 



Columbia Univebsitt, 

 October, 1908 



C Upper Monroe (including Manlius, Eondout, Cobleakill 

 and Bertie of New York). 



Middle Monroe (Sylvania sandstone, only known repre- 

 sentative). Partly marked by pronounced hiatus. 



Lower Monroe (including water limes of Ohio, marine 

 "Salina" of Maryland). 



Eepresented by the non-marine Salina sediments only in 

 North America so far as known (including Green Pond 

 and Shawangunk conglomerates and the red Longwood 



shales) . 



Guelph. 



Lockport. 



Rochester. 



Clinton. (Limestones and shales of western New York; 



Medina sandstone, including Oneida conglomerate, Tus- 



carora sandstone of Pennsylvania and Maryland and 



Clinch sandstone of Tennessee.) 

 Cape Girardeau or Alexandrian (a possible equivalent of 



some of the Clinton divisions given above). 



Richmond. 



Lorraine (including non-marine sediments; t. e., Oswego 

 and Queenston sandstones and shales of New York, etc., 

 Tyrone and Juniata conglomerates and sandstones of 

 Pennsylvania; Bays sandstone of Tennessee). 



Eden formation (probably in part represented by Tyrone 

 conglomerate). 



Utica — Trenton series. 



Black River (including Normanskill shales). 



Chazy limestone series of Lake Champlain region, and 



local facies, such as Lowville, Pamelia, Stones River, 



Chambersburg beds, etc. 



Beekmantown limestones and dolomytes, of Lake Cham- 

 plain, Deepkill and Levis shales; various local sub- 

 divisions, as Little Falls dolomyte and probably the 

 so-called " Potsdam " and Theresa formation of north- 

 west Adirondack region. 



Upper part of the St. John group of the Acadian provinces 

 and New Foundland (including Potsdamian and Sara- 

 togan as upper members, equivalent approximately to 

 Tremadoc ) . 



■ Paradoxides and Protolenus beds of Atlantic province and 

 equivalent beds of Pacific province and Appalachian 

 embayment. 



Etcheminian shales (including Coldbrookian) of Atlantic 



province (Holmia fauna). 

 Georgia lutytes and arenytes, limestones and dolomytes of 



Pacific- Appalachian province (Olenellus fauna). 



Amadeus W. Grabau 



