10 



...?S ' - "' - -- :-' 



The preceding diagram represents the series so far as it has 

 been developed in this country. In Europe, the Upper Terti- 

 ary is not unfrequently alternated with beds of fresh water 

 shells, mostly attributable to a lacustrine origin. No such ex- 

 amples have yet been noticed on this side the Atlantic. Again, 

 the European Tertiary is based upon the Chalk formation ; bu.t 

 although in the United States, no Chalk, minearologically speak- 

 ing, has been observed, Dr. Morton has shewn, in the most 

 satisfactory manner, that we possess its Geological equivalent 

 in the marl of Now Jersey, Delaware, &c. which is in fact 

 contemporaneous with the Lower Chalk or Ferruginous Sand 

 formation of Europe ; the upper mass, or Chalk of commerce, 

 being wanting. 



These formations, collectively, form the Atlantic margin of 

 the United States, from Sandy Hook, in New Jersey, to the 

 peninsula of Florida, from whence they skirt the Gulf of Mex- 

 ico to the waters of the Mississippi. Of the Geology of the 

 region west of this, very little is known ; but on Red River, shells 

 of the Ferruginous Sand formation were discovered by Mr. Nut- 

 tal during his hazardous journey through the inhospitable wilds 

 of the Arkansas territory, led solely by the love 'of Science., 

 to which Ife had nearly fallen a martyr. 



This southern portion appears to occupy a much broader 

 space than is observable in the northern sections, but the order 

 of position is of course the same in all. The same formations 

 appear to have an insulated existence in Martha's Vineyard, 

 the Elizabeth Island, Long Island, &c. on the coasts of the 

 the Eastern States. The tract to which we allude is called 

 Alluvial on Mr. Maclure's geological map of the United States ; 

 and although the name is incorrect, the geographical bounda- 

 ries there given are sufficiently accurate for general purposes. 



Let us now take a glance at the several subdivisions of the 

 Tertiary class, together with the Alluvial and Diluvial deposits 

 which are frequently found overlying them. 



Alluvium. This name is applied to all deposits derived 

 from causes now in operation. Such are the accumulations of 

 mud and other debris at the mouths and along the courses of 

 rivers ; the drifting sands of the sea coast ; peat bogs, &c. &c. 

 Of all these circumstances we see numerous examples through- 

 out the Atlantic margin of the United States, and especially in 



Ifc ;" [24] 



