378 PROCEEDINGS OF THE ACADEMY OF [189^, 



crystalline rocks of the Atlantic coast, but never before from Penn- 

 sylvania. The particular locality discovered by Mr. Dailey is in 

 the quarry just below Morgan's Station on the southeast side of 

 Chester creek, about five miles from the city of Chester. The 

 associate minerals are magnetite, hematite, green mica, quartz 

 and a flesh-colored feldspar in Avhich the crystals, about one-quarter 

 of an inch in length, were observed. Two or three perfect crys- 

 tals were found and a quantity of fragments. Mr. Dailey has sub- 

 jected his find to the following examination : 



" The best crystals were examined with the aid of a 

 polariscope, and what appeared to be parallel extinction 

 was observed, thus excluding the possibility of its being dis- 

 torted garnet, which had been suggested, and it apparently 

 confined the crystallization to practically tetragonal or 

 v^-,^^^''^ orthorhombic ; but upon looking up Monazite, which 

 ^■~^ had been suggested, the angles of extinction were found to 

 very nearly appi-oach right angles; thus the apparent parallel ex- 

 tinction of a monoclinic mineral was explained. Measurements 

 (rough, to be sure, for the surfaces did not permit the reflection 

 of a well-defined image) were made with the reflecting goniometer 

 of two angles, one of which was an essential angle. For angle 

 a w, which according to Dana is 39° 12' 30", was found 39° and 

 about 19', and angle v v, which should be 73° 19' 00", was found 

 about 73° 30'. 



A qualitative chemical analysis was thought necessary to insure 

 and corroborate the above. The pulverized fragments were taken 

 to dryness with hydrochloric acid, taken up with water and precipi- 

 tated with oxalic acid. This precipitate gave upon ignition the 

 peculiar red color of the cerium group. Another portion of pow- 

 der upon fusion wilh white flux and solution in nitric acid gave 

 with ammonium molybdate the characteristic reaction for phos- 

 phorus. 



August 8. 

 Mr. Benjamin Smith Lyman in the Chair. 

 Six persons present. 



August 22. 

 Mr. Benjamin Smith Lyman in the Chair. 

 Six persons present. 

 A paper entitled " New Species and Varieties of Mollusks from 



