XL 



ON GRANITES AND GRANITIC VEIN- 

 STONES. 



(1871-1872.) 



This paper appeared in three parts in the American Journal of Science for Feb- 

 rhary and March, 1871, and for February, 1872. The license by which the title is 

 made to include a description of certain calcareous vein-stones is explained to the 

 reader under 35-37. Parti., as originally printed, included 1-15; part II., 

 16-31; and part III., 32-49. 







CONTENTS OF SECTIONS. 1, 2. Definitions of granite and syenite ; 3. 

 Structure of granitic and gneissic rocks; 4, 5. Felsites and felsite- 

 porphyries; 6. Gneisses and granites of New England; 7. Granitic 

 dikes and granitic vein-stones; 8. Scheerer's theory of granitic veins; 

 9-10. Elie de Beaumont on granites and granitic emanations; 11. 

 Granitic distinguished from concretionary veins; 12. Von Cotta on 

 granitic veins; 13, 14. The author's views on the concretionary origin 

 of granitic veins; 15. The banded structure of granitic veins; 16. 

 Granitic veins of Maine, Brunswick; 17. Topsham, Paris; 18. West- 

 brook, Lewiston; crystalline limestones; 19. Danville, Ketchum; 20. 

 Denuded granitic masses; 21. Banded veins; Biddeford, Sherbrooke; 

 22. Veins at various New England localities; 23. Mineral species of 

 these veins; 24. Veins in erupted granites; 25. Geodes in granites; 

 26. Veins distinguished from dikes; 27. Volger and Fournet on the 

 origin of veins; 28, 29. Certain fissures and geodes distinguished from 

 veins opening to the surface; 30, 31. Temperatures of crystallization 

 of granitic minerals; 32. Laurentian gneisses; 33. Pyroxenites and 

 limestones; 34. Absence of mica-schists; 35. Classes of veins; 36. 

 Granitic vein-stones \ 37. Similar veins in Norway; 38. Minerals of 

 granitic veins ; 39. Evidences of concretionary origin ; banded structure ; 

 40. Incrustations of crystals ; 41. Skeleton-crystals ; 42. Rounded 

 crystals; 43. Quartz crystals in metalliferous veins; 44. Types of 

 vein-stones; feldspathic; 45. Calcareous vein-stones; 46. Order of suc- 

 cession of minerals; 47. Attitude of the veins; 48. Calcareous vein- 

 stones in higher rocks; 49. Supposed eruptive limestones. 



1. THE name of granite is employed to designate a sup- 

 posed eruptive or exotic unstratified composite rock, granular, 



