169 Along the northern edge, or a little outside of the northern margin of this line of serpentine, trap-rock occurs in ... The crystalline minerals of this tract, few in number, will be mentioned in a future Chapter in connection with those of the other serpentine belts. 4. ... It is evidently not in the prolongation of the long belt just described, but is almost exactly in the range of the Serpentine ... The last- mentionedanbsp;...
|Title||:||The Geology of Pennsylvania: Metamorphic strata: Gneissic rocks|
|Author||:||Pennsylvania. Geological survey, Henry Darwin Rogers|