12 THE AMERICAN MUSEUM JOURNAL 



four inches in diameter, from near Fort Washington Avenue and 

 171st Street, is in the general Museum series. 



Among other species which have been found in the granite 

 and pegmatite veins mention may be made of ahanite in the 

 form of the long, lath-like crystals known as orthite, apatite, 

 beryl, cyanite, dumortierite, iolite, monazite, ripidolite, wemer- 

 ite, xenotime and zircon. Monazite is a compound of the rare 

 elements cerium, lanthanum and didymium with phosphoric 

 acid, and is the source whence the impregnating substance for 

 the mantles of incandescent gas lights is obtained. Uraninite, 

 or pitchblende, the chief source of radium, occurs on the island. 

 Galena, the sulphide of lead, has been found in minute crystals 

 on crystals of chabazite. Gypsum in radiating crystals on mica 

 schist is one of the oddities of the collection, and fiuorite (from 

 the Subway) is another. Chrysoberyl, too, has been found in 

 one locality. Azurite and malachite occur rarely on the island. 



The limestone beds have furnished the collection with mala- 

 colite (white pyroxene), brown tourmaline and pretty groups of 

 crystals of smoky quartz. Fibrous aragonite has been taken 

 from thin veins in the limestone. 



Finally, the serpentine area yields an intimate mixture of 

 calcite and serpentine resembling the spotted green and white 

 rock called ophio-calcite. Large specimens of this peculiar rock 

 may be seen in the local rock collection in the Hall of Geology. 

 At one time this mixture aroused considerable interest from the 

 erroneous supposition that it corresponded with the famous 

 Canadian "fossil" of Archaean age, Eozoon Canadense. 



A complete list of the minerals of Manhattan Island would 

 include the names of nearly one hundred species and varieties, 

 and the region has been one of the most prolific in kinds in the 

 world. Although most of the ground is now inaccessible, that 

 which remains offers inducement to the diligent collector to 

 search for mineral treasures to add to his cabinet. 



Edmund Otis Hovey. 



Mr. Charles B. Crook has presented the Museum with an 

 elaborate feathered head-dress, once worn by an East African 

 chieftain. 



