On the Secondary and Tertiary Formations. 



islands, were never to be found by man, though eagerly sought 

 after. 



At Wilmington is another interesting locality, where not only 

 the tertiary marl corresponding to that at the natural well is 

 found, but the secondary sandstones and conglomerates below it 

 are well exposed on the banks of Cape Fear river. The lower 

 tertiary is wanting, and this marl bed, which is from two to 

 three feet thick, is seen resting upon the sandstones, containing 

 shells belonging altogether to the upper secondary formation. 

 Above the marl, and resting on it, the upper stratum observed is 

 of sand and loam, containing a {evr layers of small white peb- 

 bles. The marl is nearly as prolific in shells as the same forma- 

 tion at the natural well. The species, however, are not the same, 

 as will be seen from the appended catalogue, (p. 344.) More than 

 fifty species were collected, of which eight are recent, and those 

 in italics new. Comminuted shells and fine sand form the marl 

 stratum, and these are either converted into a solid mass not easily 

 broken, or remain unconsolidated. The sandstone beneath is in 

 one place a compact siliceous mass, but a little way off it changes 

 to a coarse pebbly rock, consisting of small, rounded quartz peb- 

 bles of a dark color ; and then again it becomes so calcareous that 

 with proper care it might be burned to tolerable lime. The peb- 

 bly rock or conglomerate contains shells, and corals, and small 

 sharks' teeth, in abundance. Large teeth are rare, as are bones, 

 which are said to have been found it. The shells themselves 

 have generally disappeared and left only the casts; these, though 

 very abundant and perfect, render it extremely difiicult to deter- 

 mine the species. The genera are principally Cyprea, Cirrus, 

 Gryphea, Ostrea, Anthophyllum, Nautilus, &c. 



The proximity of this locality to the wharves and the town of 

 Wilmington, would render it easy for strangers to obtain speci- 

 mens thence. The marl is not here esteemed as a manure, prob- 

 ably because the soil is so sandy that the shells must decompose 

 very slowly in it. By first applying large quantities of clay to 

 it, and then the marl, no doubt very beneficial effects would re- 

 sult. 



To the south of Wilmington I noticed the marl again on Lit- 

 tle river, near its mouth, just over the boundary line in South 

 Carolina. The shells closely resemble those at Wilmington, the 

 most abundant being large Areas; but they were all tightly 



