ILLUSTRATIONS 



Plate XLVII. Relations of magnetic beds to variation and dip 352 



XLVIII. Relations of magnetic beds to variation and dip 362 



XLIX. Geological map of the Felcb Mountain range - 374 



L. Geological map of a portion of tbe Crystal Falls district 450 



LI. Geological map of the Sturgeon River tongue 458 



LII. Map of exposures in sec. 7 and portions of sees. 8, 17, and 18, T. 42 N., E. 28 W 474 



LIII. Schist conglomerate from dam of Sturgeon River 476 



Fig. 15. Magnetic cross section in T. 45 N., R. 31 "W , '345 



16. Circles of attraction 346 



17. The forces acting on the dip needle „ 347 



18. Curves showing the relations between the horizontal components at the points of maxi- 



mum deflection, for rocks dipping at various angles and buried to various depths 354 



19. Truncated anticlinal fold with gently dipping limbs 364 



20. Truncated anticlinal fold with steeply dipping limbs 365 



21. Plan and cross sections of a pitching syncline - 367 



22. Magnetic map of the Gro velaud Basin 370 



23. Plan and cross sections of a pitching anticline 371 



24. Magnetic map of a single formation split by an intruded sheet 372 



327 



