GNEISSES IN THE HIGHLANDS OF NEW JERSEY 595 



and the stripping-off of the soil from a large area have disclosed the 

 structural features in a very plain manner, and the relations thus 

 revealed afford evidence toward an explanation of the processes 

 by which the structures of the rock in question have originated. 

 In this article it is proposed to give some description of the features 

 found in this locality and to present the evidence regarding the mode 

 of origin which they suggest. It has seemed desirable also to 

 consider certain of the general properties of magmas with the 

 purpose of finding an explanation for some of the phenomena 

 observed in the field. It is believed that rock-types of a similar 

 character are to be found in other portions of the area and indicate 

 a similar origin, but at the same time it is recognized that the 

 region as a whole is most complex and that this description and 

 explanation do not apply to all parts of it. 



In recent publications of the United States Geological Survey, 

 W. S. Bayley and A. C. Spencer^ have described in somewhat 

 general terms certain features of the gneisses in a manner which 

 indicates that a theory of origin similar in some respects to that 

 which will be presented here was held in view, and others^ appear 

 to have favored similar explanations. Thus far, however, descrip- 

 tions of the mode of action of the processes concerned, as illus- 

 trated by the resultant rock structures, and a discussion of the 

 conditions under which they operated, appear to be lacking. 



The quarry in question is that of the Pompton Pink Granite 

 Company,^ and is situated at the intersection of the New York, 

 Susquehanna & Western Railroad and the Greenwood Lake Branch 

 of the Erie Railroad, near the southeastern front of the Highlands. 



A number of years ago a quarry was in operation at this point 

 and a considerable amount of granite for building-purposes was 

 obtained from it. The dressed stone was of a very pleasing appear- 

 ance and was quite widely used, but difficulty was found in obtaining 



' W. S. Bayley and A. C. Spencer, Franklin Furnace Folio (1908), and Passaic 

 Folio (1908). 



^ J. V. Lewis, Annual Report of the State Geologist of New Jersey for i^oS, p. 64. 



3 1 wish to express my appreciation of the courtesy of the general manager of the 

 company, Mr. Charles H. Mclntyre, for the opportunity which was afforded to visit 

 the quarry workings and all parts of the property. 



