4 o8 THE POPULAR SCIENCE MONTHLY. 



1876. " On Strontianite and Associated Minerals in Mifflin County, Penn- 

 sylvania." 



1877-'79. Twenty-nine communications to the Mineralogical and Geological 

 Section of the Academy of Sciences of Philadelphia. 



1880. " Note on the Zodiacal Light : The Aurora and Zodiacal Light of May 

 2, 1877." 



1880. " The Antiquity of Man in Eastern America, geologically con- 

 sidered." 



1880. " The Iron Ores of the Brandon Period." 



1881. " The Antiquity and Origin of the Trenton Gravel." 



1882. Fifteen communications to the Academy of Natural Sciences of Phila- 

 delphia. 



1882. " Volcanic Dust from Krakatoa." 



1882. "The Great Terminal Moraine across Pennsylvania." 



1882. " Note on the Aurora of April 16 and 17, 1882." 



1882. " Map of the Terminal Moraine." 



1883. Eight communications to the Academy of Natural Sciences of Phila- 

 delphia. 



1883. " The Great Ice Age in Pennsylvania." 



1883. " The Geology of Philadelphia." 



1884. " Report on the Terminal Moraine in Pennsylvania and Western New 

 York. Illustrated by a Map of Pennsylvania, showing the Glaciated Re- 

 gion, etc." 



1884. "A Phosphorescent Variety of Limestone." 



1884. u Supposed Glaciation in Pennsylvania south of the Terminal Moraine." 



1884. " Marginal Karnes." 



1884. "An Interesting Mineral (Cacoclasite) from Canada." 



1885 "On a New Substance resembling Dopplerite, from a Peat Bog at 

 Scranton." 



1885. " A Great Trap Dike across Southeastern Pennsylvania." 

 1885. "Erythrite, Genthite, and Cuprite from near Philadelphia." 



1885. " The Direction of Glaciation as ascertained by the Form of the 

 Striaa." 



1885. " Some Examples of Pressure Fluxion in Pennsylvania." 



1886. " Comparative Studies upon the Glaciation of North America." 



1886. " On a Diamantiferous Peridotite and the Genesis of the Diamond." 



1887. "The Terminal Moraines of the Great Glaciers of England." 



1887. " On Some Important Extra- Morainic Lakes in Central England, North 

 America, and elsewhere, during the Period of Maximum Glaciation, and on the 

 Origin of Extra-Morainic Bowlder-Clay." 



1887. " The Matrix of the Diamond." 



1887. " On the Terminal Moraine near Manchester." 



1887. " Accounts of Some so-called ' Spiritualistic ' Seances." 



1888. " Diamonds in Meteorites." 



