5 
Lime. 
The lime bearing minerals are epidote, hornblende, garnet, and the 
plagioclase or lime-soda felspars. Calcite so valuable for its content 
of calcium carbonate, lias been found in but one instance. This was 
in a soil which bad a marl bed three feet beneath the surface. Epidote 
has been found present in all the soils examined. This is a metamor- 
pbic mineral, and its wide distribution can be accounted for by its 
mode of formation, being one of the final products from the alteration 
of the more easily decomposable minerals augite, hornblende, and micas. 
It occurs as thick fragments, showing little signs of having undergone 
chemical decomposition. 
It is epidote that furnishes the greater part of lime for many of the 
soils examined. Hornblende alters to chlorite and epidote, giving up 
some of its lime in the process of alteration. This mineral furnishes 
lime in a more easily accessible state for use by the plant than any 
except the felspars. It often occurs in fragments in which one end of 
the crystal shows alteration to epidote and the other part remains as 
hornblende. Garnet has not been found as commonly as has epidote 
and hornblende. It occurs in thick grains, often rounded in contour. 
The plagioclase felspars have been found in many of the soils of all 
three provinces of the State, however, they are most abundantly en¬ 
countered in the Mountain and Piedmont Sections. In none of the 
soils do these minerals exist to a great extent, probably due to the ease 
with which they are decomposed; supposedly giving up their lime in 
the form of carbonate. It is in the form of the felspars that lime 
under natural conditions is most available to plants in North Carolina 
soils. Also these minerals furnish much of the soda which may replace 
or drive out potash from its state of combination in the finer particles 
of soils. Augite has been found in some of the soils and is quite common 
in those of the Iredell series. 
xlnother alteraflon product of hornblende, the principal decomposition 
product of biotite, is chlorite, an aluminum, magnesium silicate. It is 
in chlorite that much of the magnesium is held in North Carolina 
soils, especially those of the Coastal Plain section. 
Phosphoric Acid. 
Apatite is the only mineral found in North Carolina soils which 
carries phosphoric acid to any extent. In very few instances has this 
mineral been found in the soils of the Coastal Plain. This is in accord 
with the total chemical analyses. The soils of the Piedmont and Moun¬ 
tain sections contain apatite to a much larger extent, but here the 
amount is only a trace. More often than otherwise, this mineral is 
found included in quartz and other minerals; in this form it is doubt¬ 
ful if the plant can draw much of its phosphoric acid from this source. 
Compared to potash, lime, and magnesia bearing minerals, apatite 
occurs as mere traces in our soils. 
Rutile, zircon, toumaline, sillimanite are common minerals of these 
soils, but as these have little or no plant food value, a description of 
them will not be given here. 
