IGNEOUS AND CRYSTALLINE ROCKS. 35 
F. Sericite schist, Ladiesburg. Described by Bayley in Bull. 150, p. 317. Con- 
tains quartz, sericite, chlorite, a mineral thought to be kaolin, zircon, iron oxide, 
and rutile. Analysis by George Steiger, record No. 1600. P. R. C. 126. 
G. Another sample of F. Analysis by Schneider, No. 1370. 
H. Metarhyolite, south of Port Deposit. Dike. Vulcanose. Described by F. 
Bascom, in Maryland Geological Survey, Cecil County volume, p. 136. Contains 
quartz, orthoclase, plagioclase, biotite, and hornblende, with accessory magnetite, 
apatite, titanite, garnet, pyrrhotite, and muscovite, and secondary chlorite and 
epidote. Analysis by W. F. Hillebrand, record No. 1928, P. R. C. 1706. 
99.68 | 100. 29 99. 93 
a Uncertain because sulphides are present. 
VIRGINIA: 
A. Andesite, 3} miles east of Front Royal. SR. 4 of orendase. Described by Keith 
in 14th Ann., p. 305. Intermediate between diabase and quartz porphyry. Contains 
plagioclase, quartz, magnetite, ilmenite, and a little epidote. Analysis by George 
Steiger, record No. 1450. 
B. Porphyritic felsite or felsophyre, forks of Straight Creek, 3 miles east-northeast 
of Monterey. Toscanose. Described by Darton and Keith in Am. Jour. Sci.. 4th 
ser., vol. 6, p. 305. Contains phenocrysts of biotite, orthoclase, and plagioclase, the 
mica and feldspar being about equal in amount. In the groundmass are feldspar, 
quartz, magnetite, or ilmenite, and a little secondary chlorite with less muscovite. 
No glass. Analysis by Hillebrand, record No. 1665. P. R, C. 342. 
