472 T. L. WATSON WEATHERING OF ALLANITE 



and Philadelphia counties, in the southeastern part of the State. It is 

 found chiefly as crystals and crystalline masses in pegmatite dikes, asso- 

 ciated with mica, ilmenite, zircon, and a variety of other accessory min- 

 erals, chiefly the rare earths.*^ Analyses Y, VI, VIII, and IX of table 

 on page 474 are of allanite from different localities in Pennsylvania. 



Along the belt of Precambrian rocks extending through Northampton, 

 Lehigh, and Berks counties, allanite^^^ is of common occurrence as a con- 

 stituent of pegmatite, in much of Avhich it is the only accessory mineral. 

 The grains are usually only a few millimeters in diameter, but locally 

 attaining 30 or 40 centimeters. The most important localities in this 

 region are: One mile south of Redington, Lower Saucon township, 

 Northampton County (the source of material analyzed from "Bethle- 

 hem," Pennsylvania) ; South Mountain, south of South Bethlehem, where 

 a mass weighing 1.00 pounds was obtained; Colesville, Lehigh County, 

 where a large specimen of lanthanite was at one time found, resulting 

 from the decomposition of the allanite; Pricetown, Berks County, where 

 it is associated with ilmenite, and McKnights Gap, northeast of Reading, 

 Berks County, where large masses have recently been obtained. 



The pegmatites of the southeastern belt of Precambrian rocks, which 

 extends from Bucks to Chester counties and through the northern part 

 of the city of Philadelphia, also contain allanite occasionally, but it is 

 here usually associated with a variety of other accessory minerals. Im- 

 portant localities are : Hoffmans quarry, Frankf ord, Philadelphia, where 

 it is associated with scheelite; Johnsons quarry, Morton, Delaware 

 County, where euxenite, columbite, and other rare earth minerals accom- 

 pany it, and East Bradford township, Chester County, where it is not 

 found in place, but is plowed up in the fields, and is accordingly more 

 extensively weathered than in most other occurrences. 



Specimens of massive allanite from East Bradford, Chester County, 



*^ The following references refer chiefly to analyses : 



E. S. Dana : A System of Mineralogy, 1900, p. 525. 



C. Hlntze: Handbuch der Mineralogie, 1897, pp. 269-270. 



F. H. Genth : Am. Jour. Sci., vol. 19, 1855, p. 20. 

 C. F. Rammelsberg : Pogg. Ann., Bd. 80, p. 285. 



Nils Bngstrom : Groth's Zeitschr., Bd. 3, p. 194. 

 ^•'a The references here given refer to descriptions of occurrences of allanite: 



F. A. Genth : Mineralogy of Pennsylvania, Kept. B, Second Geol. Survey Pa., 1874, 

 pp. 79-80. 



.John Eyerman : Mineralogy of Pennsylvania, Private Publications, pt. i, 1889, p. 

 20; pt. ii, 1911, p. 10'. 



Edgar T. Wherry : Radioactive minerals found in Pennsylvania. Jour. Franklin 

 Institute, vol. 165, 1908, pp. 67, 70, and 75-78. 



Elmer Benge and Edgar T. Wherry : Directory of the mineral localities in and 

 around Philadelphia. Mineral Collector, vols. 12-15, 1905-1908 ; numerous mentions of 

 allanite. 



