UNAKITE TYPE 223 



at least the now highly epidotized portions of rock yielding the type 

 unakite represent magmatic segregations or secretions similar to schlieren 

 or possibly pegmatite, some of whose original constituents have been 

 altered to epidote chiefly by hydrometamorphism. 



ZIRGONIFEROUS EPIDOSITE 



In the syenite areas north of James Eiver fragments of highly epi- 

 dotized rock occur, many of which are rich in ilmenite, apatite, and 

 zircon. The rock is found in largest quantity on the southeast slope of 

 the Blue Ridge in the Beverly Settlement in Amherst County. The rock 

 was not found in place, but the loose fragments were associated with those 

 of syenite in such fashion as to suggest its probable occurrence as possible 

 segregations in the syenite. It certainly seems possible that it has a sim- 

 ilar genesis to that of the probable related type, unakite. In hand speci- 

 mens of the rock the minerals easily recognized are, named in order of 

 abundance, epidote, quartz, ilmenite, zircon, and apatite. Epidote and 

 quartz compose the bulk of the rock, with the former greatly in excess. 

 The ilmenite, zircon, and apatite are not distributed uniformly through 

 the rock, but are grouped in close association with each other in irregular 

 areas. Each of these minerals varies greatly in amount in the different 

 hand specimens. 



Zircon occurs in small crystals of light reddish-brown color (colorless 

 in thin .sections), and at least 50 were removed from a single small speci- 

 men of the rock. The largest crystal measured 2.5 millimeters in length 

 and 1 millimeter in thickness. 



Microscopic study of thin sections gave no additional information from 

 that gained by megascopic study of hand specimens as to the character of 

 the rock. 



Geanite 



Field investigation of many of the syenite areas in the Blue Ridge dis- 

 closes the association of more acidic rocks of granitic composition in 

 which quartz usually becomes very abundant. Orthoclase (microcline) 

 is increased in amount and the plagioclase constituent is more sodic. 

 Mafic minerals are decreased in amount and in some instances they fail 

 almost entirely. Like the syenite, the weathered portions of the granite 

 show characteristic pitted surfaces. The pitting from weathering and 

 disappearance chiefly of the feldspar has left the quartz in projecting 

 reticulated areas in the more massive phases of the rock and in more or 

 less drawn out connecting spindles in the more gneissic phases. 



The exact field relations of the granite and syenite have not been defi- 



