80 The Cambrian Bocks of North America. 



is 2700 feet in thickness, and contains higher up a fauna com- 

 pared with that of the Chazy, together with some forms character- 

 istic of the Trenton, the succession thus showing a gradual 

 passage from the first to the second fauna.] 



For the better understanding of the above remarks, and of the 

 relation of the American Cambrian in its eastern area to the 

 Ordovieian and Silurian above and the Taconian and still older 

 Eozoic series below, we append a tabular view from the author's 

 memoir on The Taconic Question, Part 1., recently published 

 in the first volume of the Transactions of the Royal Society of 

 Canada. In this table are seen the classification and nomenclature 

 proposed by Amos Eaton half a century since, together with the 

 more recent names. The Potsdam sandstone, which in j>artsofthe 

 Adirondack area forms the base of the Cambrian, had not at that 

 time been recognized. 



(See next page.") 



