NORTH-CAEOLINA GEOLOGICAL SURVEY. 



it is about one foot high, when it turns yellow and dies. It 

 is then evidently in an uncultivated condition. 



The question then comes up, can the open prairie be made 

 cultivable artificially, and if so, how ? The question first put 

 is not designed to inquire strictly into the possibility of the 

 tiling, because all who have given some thought to the ques- 

 tion, know very well that it is possible, because a soil can be 

 made from the start, by putting together the proper elements, 

 and this can be done with the open ground prairie ; but can 

 it be done profitably ? Now, when we are assured that the 

 soil of the open prairie ground is composed exclusively of vege- 

 table matter, it is plain, that the earths must be added to give 

 it the composition required for the perfection of vegetables 

 of any value to man. The old practice consisted mainly, in 

 giving peaty soils (as this must be ranked in that class,) a 

 heavy dressing of lime. It is evident on reflection, if the 

 principles in the foregoing paragraphs are correct, that this 

 practice could not be relied upon, for it would only acquire 

 a single element. Something more is wanted. Not only 

 lime, but iron, alumina and silica are required. We may 

 infer that the phosphates and alkalies will be supplied by the 

 decay of vegetable matter, and, from this fact, ii; appears 

 at least plausible, that the treatment which the open ground 

 prairie demands, is the addition of some natural soil. It may 

 be taken from the nearest marsh where mud or soil may be 

 obtained, provided it contains silex, alumina, iron, etc. 



Knowing, then, what substances are wanting in this soil. 

 and hence what must be added, the question resolves itself 

 into this : how much does a soil of the description of that 

 under consideration require to make it productive? We 

 have seen that the soil upon Croatan sound is at least tolera- 

 bly productive, which contains only 7.30 per cent, of inor- 

 ganic matter, and that the element which greatly predomi- 

 nates over the rest, is sand, in a state unfitted to furnish solu- 

 ble silica. We may regard the Croatan soil as containing 

 the smallest quantity of earthy matter, and at the same time 

 possessing the ability to grow the cereals. Leaving the sand 

 out of view, we may infer that the least quantity of earth which 

 3 



