230 TRANSACTIONS OF THE [APRIL 19, 



terminations, though never of conspicuous size. Tiiese arc often 

 grouped into handsome specimens and may be also obtained iso- 

 lated in considerable quantity wherever masses of tlie cellular 

 quartz are broken into fragments. 



The cretaceous formation along tiie southern section of the 

 island presents features of some interest to the mineralogist. 



In the deposits of fire-clay and kaolin may occasionally be 

 found lignite and nodules oi pi/rite and liDwiiite. 



Tlie igneous rocks are represented by the trap dyke along the 

 western portion of the island. This dyke is a continuation of 

 the Palisade range which commences at Ladentown, Eockland 

 •County, over fifty miles distant. Tiiis ridge is of no great ele- 

 vation on the island, and is covered by several feet of drift. 



Tlie rock is quarried for paving stone. Its yield of minerals 

 is quite limited. Tlie most intercsLing of these is a greenish 

 -albitein finely modified tabular crystals, found at tlie Port Rich- 

 mond quarry. 



The crystals have a high lustre and are finely striated. They 

 are accompanied by small sections of ice-spar, a purplish mica, 

 .and a dark mineral resembling chlorite. 



Finally, the mineralogist may keep an observing eye on the 

 drift material,, especially that along the eastern and southern 

 -coasts of the island. Eepresentatives of the primitive rocks will 

 be found in abundance with an occasional fossil, a wanderer 

 from some far distant locality. The moraines mark the south- 

 ernmost limit of the great glaciers. 



Prof. D. S. Martin gave a summary of the geology of 

 Staten Island, and exhibited specimens of its rocks and ores. 



President Newberry described some of the geologic features 

 of Staten Island which have an influence upon the sanitary con- 

 dition of the region. 



Remarks were made by Dr. Friedrich and Mr. Kunz. 



