112 Adams and Coker — Elastic Constants of Rocks. 



The sixteen rocks whose elastic constants were determined 

 are enumerated in the following list : 



Marbles and Limestones. 



1. Black Belgian marble ; an extremely fine-grained and mass- 

 ive black marble, largely used for ornamental purposes and known 

 in trade as " Belgian Black ". 



2. White marble, Carrara, Italy ; a typical fine-grained sac- 

 charoidal marble. 



3. White marble, Vermont, U. S. A.; identical in appearance 

 with the last. 



4. Pink marble, Tennessee, U. S. A.; a highly metamorphosed 

 coralline limestone which has been converted into a marble ; 

 largely used for purposes of construction and known as " Pink 

 Tennessee." 



5. Trenton limestone, Montreal, Canada; a highly fossilifer- 

 ous variety, free from any signs of stratification, taken from a 

 heavy bed in the Mile End quarries at this place ; used exten- 

 sively as a building stone. 



Granites. 



6. Granite, Baveno, Italy ; a typical biotite granite of medium 

 grain. 



7. Granite, Peterhead, Scotland ; a typical, rather coarse- 

 grained, biotite granite. 



8. Granite, Lily Lake, New Brunswick, Canada ; closely resem- 

 bles No. 7. 



9. Granite, Westerly, Rhode Island, U. S. A.; a typical, very 

 fine-grained reddish biotite granite. 



10. Granite, Quincy, Massachusetts, IT. S. A.; a rather coarse- 

 grained hornblende pyroxene granite. 



11. Granite, Stanstead, Quebec, Canada; a rather fine-grained 

 muscovite biotite granite ; the mica is relatively more abundant 

 than in either the Peterhead or the Westerly granites. 



JVepheline Syenite. 



12. Nepheline syenite, Montreal, Canada; a typical fine-grained 

 massive hornblende nepheline syenite. 



Basic Plutonic Hocks. 



13. Anorthosite, New Glasgow, Quebec, Canada ; a rock com- 

 posed of plagioclase with a subordinate amount of pale green 

 augite and green hornblende ; it is fine in grain and very tough, 

 being used for paving sets in the city of Montreal. 



14. Essexite, Mount Johnson, Quebec, Canada; a typical essex- 

 ite, massive and uniform in character, composed of plagioclase, 

 nepheline, augite, hornblende and biotite ; used extensively as a 

 building stone and for monuments. 



15. Gabbro, New Glasgow, Quebec, Canada ; this rock is deep 

 green in color and occurs in the form of a large dike cutting 

 the anorthosite (No. 13) ; composed of augite, hornblende and 

 plagioclase, the two former minerals preponderating largely. It 



