THE LEOPARDITE OF NORTH CAROLINA 



221 



clase, and untwinned orthoclase. These are frequently rendered 

 nearly opaque from innumerable, closely crowded, dark inclusions 

 not identifiable, along with minute spangles of colorless mica. Zonal 

 structure is rarely observed, and cleavage is usually wanting. Around 

 the borders of several of the feldspar phenocrysts slight embayments, 

 produced by incipient resorption, are noticeable. 



Fig. 3. — View showing partially spotted and partially streaked rock, with tend- 

 ency toward arborescent form manifested near the middle of the picture. Surface 

 broken at an angle intermediate between that of Figs, i and 2. Photographed 

 from hand specimen. One-half natural size. 



Several of the sections were so cut as to include areas of the black 

 pencils which characterize the rock, megascopically. These are dis- 

 tinguished, microscopically, from the white portions of the groundmass 

 only by a distinct medium-to-dark yellowish-brown staining, some- 

 what resembhng that of limonite stain frequently observed discoloring 

 tiny areas of the rock, derived from the partial leaching of any iron- 

 bearing constituent in igneous rocks. No definite source of the 

 staining was entirely indicated in any of the sections, but the areas 

 clearly represent percolation of solutions of manganese and iron 



