ECONOMICAL GEOLOGY. 
191 
advantage in many places. Mr. Flowers, above mentioned, states that 
an application of five to seven hundred bushels to the acre has sometimes 
more than quadrupled the crop of corn, and Mr. J. F. Oliver, 3 miles 
further down, prefers the greensand to the more calcareous shell marls. 
And Dr. Emmons states that Gov. Clark had used the marl, marked C” 
with good success for many years. Some of the analyses given above 
show a large percentage of sulphuric acid, (sulphate of iron), as Nos. 1, 
4, 7. These must be used with some caution on account of their acid 
quality. They should he thrown out of the pits long before using and 
exposed to the leaching action of the rains ; or better, treated with a 
small percentage of lime or of shell marl, which would not only correct 
the acidity, but increase the value by replacing the sulphuric acid with 
gypsum. 
The quantity of marl which may be profitably used' varies with its 
quality and the condition of the land. But these greensand marls may 
be applied in quantities of from 500 to 1000 bushels per acre. The 
richer marls of New Jersey are applied in quantities varying from 100 to 
500 or even 600 bushels. But it happens in this state generally, that 
where this species of marl is found, the better qualities of shell marl are 
also accessible, and, requiring to he used in much smaller quantities, they 
are much cheaper. But where these cannot he had, the greensand marls 
are unquestionably well worthy of the attention of the farmer. Their 
distribution is easily seen by a glance at the map. They come to the sur- 
face, as stated, along the banks of the Cape Fear and Livingston’s Creek, 
on Black River and South River, on the Neuse and its tributaries about 
and below Kinston, along the Contentnea and Moccasin, and at a few 
points even as far north as the Tar River. 
Eocene Marl. The marls of the next formation, which are always 
found overlying the preceding, when the two occur together, are, as 
already described in another connection, either a calcareous sand, pass- 
ingin places into a friable sandstone, coarse, or fine, or a fine calcareous 
clay, or a conglomerate shell limestone, more or less compact and occasion- 
ally semicrystalline. They are composed of comminuted shells, corals 
and other marine exuviae. The extent, and many localities of outcrops 
of these marls, have been previously noted. The following analyses will 
show their chemical constitution and agricultural value: 
S 
9 
10 
11 
12 
13 
Silica, 
3.54 
4.95 
1.22 
7.27 
20.39 
40.11 
Ox. of Iron and Alum. 
0.97 
2.30 
1.30 
1.63 
3. S3 
5.23 
Lime, 
51.74 
50.59 
52.90 
4S.55 
39.96 
27.73 
