. 
100 Billings on the age of the so-called Potsdam Rocks 
Art. XIII.—Further observations on the age of the Red sandrock 
formation (Potsdam group) of Canada and Vermont; by E. 
ac F.G.8., Palzontologist of the Geological Survey of 
Canada. 
1. Qurstions oF Prioriry. 
mind that since Emmons first published his Taconic System both 
Sir Roderick Murchison and Barrande have extended the Lower 
orin the base of the Lower Silurian as the formation is noW 
ni The age of the ape at Point Levi opposite Que 
= 
£ 
