NOKTH-CAROLINA GEOLOGICAL SURVEY. 45 



sary in the first place to inquire into its physical condition 

 to ascertain its texture, the size of its particles, and at the 

 same time ascertain whether they are silicious and coarse, 

 and insusceptible of retaining water or fertilizing matter. 



Many examples of these unproductive tracts belong, geo- 

 logically, to the most recent formation, as the Postpliocene of 

 authors. They are properly marine formations, in which 

 sand, as will be seen in the sequel, forms the largest propor- 

 tion of the elements of the compound. 



A specimen of the unproductive soil was received from D. 

 A. Humphrey, Esq., of Swansboro', Onslow county, accom- 

 panied with a letter containing a brief account of the mate- 

 rial under consideration, the copy of which is in the follow- 

 ing words : 



SWANSBORO', N. C., Jan., 1858. 



DEAR SIR : You will remember, that at Beaufort, last May, when I had 

 the pleasure of an introduction to you, you told me if I would send you a 

 specimen of some of that peculiar land of which we talked, you would an- 

 alyze and inform me of its constituents, and advise me of the necessary 

 change to be made in it, so as to make it produce the ordinary crops. 



The land from which this specimen was taken produces weeds and vege- 

 tables common to all the sound land, very scantily, except the sweet fennel 

 (Foenicuhim) which grows very luxuriantly, so large even, that I have 

 them taken up with a grub-hoe. It will produce, with the best cultivation, 

 (without manure,) say 100 Ibs. seed cotton to the acre, and one bushel corn. 

 When the corn first springs up, it grows rapidly for a short time ; then 

 turns yellow and falls. The land is quite elevated. I have shipped to 

 Wilmington a small bag containing the specimen, from which place you 

 will soon receive it, and when it suits your convenience to examine, please 

 do so, and let me hear from you. 



And oblige, very much, 



Your friend and humble serv't, 



D. A. HUMPHREY. 



PROP. E. EMMONS, Raleigh, N. C. 



On submitting the soil described in the foregoing letter, I 

 found it composed of the following elements : 



Silex, 85.200 



Peroxide of iron and alumina, 2.862 



