114 TRANSACTIONS OF THE [aPR. 6, 



tion of the outcrop remaining at 144th street and Seventh ave- 

 nue. He remarks on the resemblance of the rock to the Manay- 

 uuk schists of Hall, and suggests that it be examined. 



I went up there and obtained photographs and specimens, and 

 noted the following. The strata, of gray gneiss, are much con- 

 torted and show a number of synclinals, a large one, in the centre 

 of the outcrop, being of a compact gneiss in which feldspar pre- 

 dominates. Scattered through the rock are segregated veins 

 of pegmatite, while cutting directly across the strata, with a dip 

 of 30° W., is a vein of granite. This vein may be seen on the 

 south end of the outcrop, and also on the north side of 144th 

 street. 



At 143d street and Seventh avenue is an outcrop of a dark- 

 colored, fine-grained mica schist. This outcrop also contains 

 several granite veins, cutting across the strata, and one of them 

 being branched. These two rock outcrops are thus specially 

 interesting on account of these veins, which seem to be injected 

 rather than segregated ones, with the exception of the pegma- 

 tite veins previously mentioned. The outcrops do not, as sug- 

 gested by Mr. Rand, throw any further light upon the question 

 of the exact geological age of the rocks of Manhattan Island. 



The following papers were read by W. Goold Levison: 



I. NOTE ON AN ECONOMICAL ZINC ELEMENT FOR BUNSEN 



BATTERIES, 



illustrated by apparatus. 



This modification consists in using a number of zinc plates 

 clamped to a brass collar by set screws. It is claimed that by 

 this means greater surface and consequently greater efficiency 

 is gained. If one or more plates are used up, new ones may 

 be inserted with ease, and need not interrupt the action of the 

 apparatus. 



II. NOTE ON PHOTOMICROGRAPHS FROM PHOTOGRAPHS OF 



LIGHTNING, 



illustrated by lantern slides. 



