336 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



with which to confront other palaeozoic basins. The materials have 

 been scrupulously selected from the best authorities ; — from the 

 able reports of the State Geologists of New York, and from the admi- 

 rable researches of De Verneuil and Sharpe ; introducing also some 

 observations of my own, for it has been my privilege to visit many 

 of the most interesting localities, and very much of the whole region. 

 The palaeontological portion of this Synopsis is not taken from 

 the promiscuous statements of authors, but is based upon a series 

 of elaborate Tables constructed by myself from the writings of James 

 Hall, Vanuxem, Conrad, De Verneuil, Sharpe, Portlock, Salter, 

 Sowerby, Morris, M'Coy, and others. It is true that the fossils of 

 North America still require some revision ; but I am encouraged to 

 believe, from the universally admitted competency of the palaeon- 

 tologists spoken of above, — that of James Hall vouched for byAgassiz 

 and De Verneuil after personal examination, — that my Tables contain 

 a great body of truth, to which day after day will only add. 



In this Synopsis nothing theoretical has been admitted, as far as 

 I recollect; but valuable facts occurring beyond the limits of the 

 State of New York have been placed at the foot of the page, and only 

 introduced into the general letter-press on unavoidable occasions. 

 At the end of the paper has been appended a short series of in- 

 ferences, interesting as they appear to me, which result from the 

 facts narrated, and are to be treated on in a few forthcoming papers, 

 mostly ready. 



The best notion of the figure, extent, and relations of the State of 

 New York will be obtained by looking at the Geological Map of 

 Middle North-east America now before you*. New York extends 

 from east to west 408 miles, and 310 miles north and south; but 

 in a north-east and south-western direction this State attains the 

 length of 450 miles, in round numbers. It narrows at its west end 

 to nearly 40 miles. Along the south side of Lake Ontario its north 

 and south dimension varies from 90 to 110 miles. Two-thirds of 

 the superficial extent of New York are to the east of Lake Ontario. 

 To treat of the boundaries of New York, political or natural, does 

 not seem to be called for here. 



Th? territory which we have been roughly measuring contains the 

 north-eastern portion of the great central basin or area of the palaeo- 

 zoic rocks of Middle North America. 



This is not the place to describe it, further than to say that it 

 occupies the northern, western, and southern parts of the United 

 States, as far west from Lake Champlain as the parallel of longitude 

 97°, some distance west of the River Missouri ; and as far south-west 

 as latitude 33°, about Tuscaloosa in Alabama ; each traverse being 

 not far from 1500 miles long, and exhibiting a series of palaeozoic 

 rocks of unequalled magnitude, symmetry, and simplicity. Beyond 

 these distant southern and western districts, the central basin sinks 

 under rocks of the cretaceous and tertiary epochs. 



* The Map referred to, comprehending Canada and the United States, is a 

 large geological map, constructed by the author, on the scale of 16 miles to an 

 inch, and exhibited to the Meeting when this paper was read. — Edit. 



