LITHOLOGICAL NOTES ON CONTACT PHENOMENA IN 
SOUTH CAROLINA. 
By Gary F. Richards. 
[Read Before Denison Scientific Association, May, 1888,] 
The rocks treated in this article are from Spartanburg Co. , South 
Carolina. They were obtained by Prof. Herrick, while on a geolog- 
ical trip through those states last summer vacation, and kindly given 
to me for study. Part of the slides were made by the Professor, the 
rest by the writer. 
The first sample is from a dyke lying near Pacolet Mills, S. C., 
which stretches from north-east to south-west for about five miles in 
an irregular boss, forty feet wide at the point viewed. Two miles to 
the east of the dyke is a large granite area which disappears beneath 
gneiss as we approach the dyke. This is lost just west of the dyke 
and schist takes its place, which is traced through its different varie- 
ties for two miles, when“we arrive at a pure steatite rock. The sec- 
tion of that district would be as follows : First the granite underlying 
the whole, on this would be found the gneiss, and lying on that the 
schist ; the dyke perforating the granite and gneiss ; the whole uncon- 
forniable. 
The hand sample, taken from within the dyke towards the centre^ 
is dark gray, almost black, and presents a fine crystalline structure ; 
the lath-shaped crystals stand out quite distinctly. Studied microscop- 
ically, the section presents a field of which nearly one-half is plagio- 
clase, in long lath-shaped crystals. Th,e plagioclase is labradorite, and 
the twinning is mostly after the albite law, but there are some beauti- 
fub examples of pereklite twins. Interpenetration of the plagioclase is 
quite common in this section, and several of the crystals show indica- 
tions of having been formed under pressure. The plagioclase was the 
first formed mineral, as indicated by the regularity of its outline. Aug- 
