166 PROCEEDINGS OF THE ALBANY MEETING 



the distinctly foliated gneisses also are frequently so filled with inclusions as 

 to suggest a conglomeratic origin. In an endeavor to work out the explanation 

 of these features, evidence has been found which points distinctly to a deriva- 

 tion of the igneous masses (in large part at least) from the previously formed 

 schists. The nature of the evidence was described and a series of polished 

 specimens was exhibited, illustrating certain prominent features resulting from 

 the operation of the processes, such as the initial localized softening of the 

 country rock and successively later stages of disintegration and fusion; the 

 manner in which inclusions in the magma become shredded and assimilated; 

 effects of diffusion in producing banded structure in inclusions ; the straining 

 off of liquid magma from suspended matter; the production of gneissic folia 

 tion from the parallel orientation of suspended shreds, etcetera. 



Presented in abstract extemporaneously. 



PREGAMBRIAN SEDIMENTARY ROCKS IN THE HIGHLANDS OF EASTERN 



PENNSYLVANIA 



BY EDGAR T. WHEREY 



(Al)stract) 



The Precambrian rocks of the highlands of Pennsylvania include several 

 formations of sedimentary origin, in part not heretofore recognized. These 

 comprise crystalline limestone, quartz-mica schist, graphite-bearing quartzite, 

 and several types of gneiss. The petrographic characters of these formations 

 are described and the mineralogical and structural criteria indicating their 

 sedimentary origin discussed. Injection, feldspathization, and assimilation are 

 shown to have been effective in developing gneisses from the sedimentary rocks. 



Presented in abstract extemporaneously. 

 At this point recess was taken. 



The Society reconvened at 2.30 o'clock. President Clarke, presiding, 

 announced that the regular program for the afternoon would begin with 

 a Symposium on the Geology of Petroleum, as follows : 



GENERAL GEOLOGICAL CONDITIONS AND FUTURE SUPPLY 

 BY RALPH ARNOLD 



In the absence of the author, this paper was read by Doctor Clarke. 



APPALACHIAN OIL FIELDS 

 BY M. L. FULLER 



ILLINOIS OIL FIELD 

 BY FRED H. KAY 



OHIO-INDIANA OIL FIELD 

 BY J. A. BOWNOCKER 



