INDEX TO VOLUME V. 



REFERENCES ARE TO THE PAGES. 



[MOST OP THE ROCK AND MINERAL REFERENCES SHOULD BE LOOKED FOR IN THE 

 ANALYTICAL KEY, WHICH IS AT THE END OF TABLE OF CONTENTS.] 



Abita, lake, rocks from, 482. 



Actinolito, as a rock-forming mineral, 960. 



Adams, F. D., on composition of gneiss, 31. 



Additional facts, 994. 



Adularia, 943. - 



Agate bay, 184, 466. 



rocks from, 170-174. 

 Agglomerate, Ely, 733, 734. 

 Aitkin county, quartzyte, 58. 

 Akeley lake, rocks from, 695-699. 

 sills, 60. 



greenstone transition to muscovadyte, 982. 

 Albite, as a rock-forming mineral, 943. 

 Algoma, rocks from, 747, 748. 

 Algonkian, non-use of term, 13. 

 Alkaline magma, characteristic elements, .'59. 

 facts of field observation, 30. 



" petrographical significance, 31. 

 order of generation of new minerals, 39. 

 Allen Junction, rocks from, 765. 

 Alpha lake, 714. 

 Amoeba lake, rocks from, 905. 

 Analyses, see chemical analyses. 

 Andesyte, analysis, 519. 

 Animikie, age of. 17. 



conglomerate at base, 44, 989. 

 Duluth, 50. 

 effect of gabbro on, 61. 

 extent, 48. 



Grand Portage graywacke, 46. 

 iron-bearing member. 45, 990. 

 referred to Keewatin, 12, 48. 

 -limestone." 45,312,991. 



magnetic iron ore referred to Keewatin, 12, 48. 

 metamorphism, 50, 61. 

 summit of, 46. 

 upper or slaty member, 46. 

 volcanic action at opening of, 989. 

 Anomalous facts, 991, 993. 

 Anorthite, as a rock-forming mineral, 944. 

 Anorthoclase, 214. 

 analyses, 666, 897. 

 as a rock-forming mineral, 944. 

 Anorthosyte, i)5. 



I {caver bay, 185. 

 Castle Danger, 187. 

 manner of origin, 65, 830. 

 Splitrock point, 180, 182. 

 Apatite, as a rock-forming mineral, 947. 

 Apobsidian, analyst's, 156. 191. 

 Beaver Bay, 190. 195. 



Duluth, 155. 

 origin, 981. 



Aporhyolyte, analyses. 211, 217, 256. 

 Beaver bay, 193. 

 Duluth, 136, 139. 

 great palisades, 211. 

 Aqueo-igneous fusion, 38. 

 Archean, definition of, 1. 

 fragmental rocks, 1. 

 conglomerate and graywacke, 5. 

 distribution, 8. 

 metamorphism, 9, 973. 

 nature of, 1. 

 origin, 6. 



rareness of shearing, 971. 

 stratigraphic structure, 12. 

 nomenclature 13. 

 Lower Keewatin, 13. 

 Upper Keewatin, 16. 

 gabbro, 15, 972, 979. 

 igneous rocks, 18. 

 genesis, 21. 

 greenstones, 21. 

 granites, 19. 



distribution, 20. 

 greenstones, 18, 987. 

 nature of, 18. 

 origin of granites, 27, 972. 

 alkaline magma, 28, 30. 

 characteristic elements, 39. 

 facts of field observation, 30, 981. 



petrographical significance, 31, 983. 

 order of generation of new materials, 37. 

 oldest quartz-porphyry, 41, 976. 

 oldest known rocks, 987. 



Armstrong bay, Vermilion lake, rocks from, 342. 

 Arrow lake, rocks from, 306, 307. 

 Ash lake, rocks from, 535, 657. 

 Ashley, 566. . 



Augite, analyses, 662, 897. 



as a rock-forming mineral, 952. 

 Kekequabic granite, 34, 897. 

 Augite-syenyte, of the Keweenawan, 979. 

 Aurora mine, 810. 



Avis island, rocks from, 357, 602, 603. 

 Baptism river, 247. 



rocks from, 218-224. 

 Baraboo quartzyte, 54. 

 Barite, in veins, Pigeon point, 947. 

 Barron county quartzyte, 54. 



