tftAy* l>>^' 



\ ALLEY OF THE MISSISSIPPI. 33 



Having thus taken a cursory, but imperfect view 

 •f the great tabular formation of secondary calca- 

 reous rock, which gives place to the immense plains 

 and lakes of the western states and territories, we 

 shall next proceed to offer a few remarks upon the 

 ancient maritime alluvium, and a flcetz formation 

 apparently connected with it, which continues from 

 Rhode Island to the coast of the Gulf of Mexico, 

 principally with a view to ascertain its south-west- 

 ern limits, and to observe the influence which it has 

 bad in producing the present character of that part 

 of the Mississippi valley. The accurate and com- 

 prehensive view of this formation, as well as of all 

 the others composing the North American continent, 

 by our absent president,* the result of observa- 

 tions continued for many years in succession, leaves 

 us little more to do than corroborate his assertions by 

 additional details, and an extension of its limits into 

 the remoter territories of the Union. 



§ II, LIMITS AND CHARACTER OF THE ANCIENT 

 MARITIME ALLUVIUM. 



The extent of the primeval ocean, and the vast 

 agency which it has exercised over our globe, to ren- 

 der it habitable, and thus to complete the plan of 

 creation, is evinced by a vast proportion of its sur- 

 face wherever our observations are directed. That 



* William Maclure, Esq 

 A 



