98 ON THE SECONDARY AND TERTIARY FORMATIONS 



Not far from Ihis place, is that interesting locality in Duplin 

 county, called the " natural u'dV It is two miles west of the 

 rail-road, (forty-seven miles from Wilmington,) on the road from 

 Kenansville to Elizabeth, Baden county. Before reaching it, 

 one may notice by the side of the road a large sink-hole, fifteen 

 feet deep, overgrown by trees and bushes ; a little beyond this, a 

 path turns off to the left to the cabin of a Mr. John Smith, within 

 two hundred yai-ds of which, in the woods, is the well. It is a 

 large circular basin, about twenty yards across, and sixteen feet 

 deep to the surface of the water ; its banks are nearly vertical, 

 although the strata are entirely obscured by the loose sand, trees 

 and bushes that have covered them, excepting in one naiTOWspot, 

 where a correct section may be obtained and specimens col- 

 lected. The soil, which is sand and yellow loam, a little clayey 

 at bottom, is from tlu-ee to four feet thick. It rests on the shell 

 marl, which is about four feet thick, and under this is a tough 

 blue clay from six to eight feet thick, overlying a sandstone like 

 the clay in color, the lowest visible rock. The marl consists 

 entirely of shells, and fragments of shells, wdth a very small 

 quantity only of fine white sUiceous sand. The shells are of a 

 great variety of species belonging to this formation, and they lie 

 promiscuously together in great confusion ; single valves of the 

 bivalves are more frequently found than the two together, and 

 even the stronger univalves are most often seen in fragments. 

 So abundant are they, that in cleaning out some of the larger 

 shells a great number of small and more perfect specimens were 

 found in their interior, and added to my collection. A Pectun- 

 cuius quinque-rug-atus, in particular, enclosed bet^veen its t^vo 

 valves a multitude of sheDs and fragments closely embedded in 

 a fine, clear quartz sand. The contents when picked out occu- 

 pied a space full twice that in which they were so closely 

 packed. Although the diameter of the Pectuncvilus was only 

 two inches and one fourth, there were in it a Cytherea reporta, 

 beautifully preserved with its natural polish, one and one third of 

 an inch long, and itself filled with other smaller shells and a 

 purer sand ihau ihat which surrounded it — several small Ostrece 

 Corbulcc, and dui)lica1{>s of twenty or tliii'ty other species. There 



