34  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1906,  PART    I. 
Carboniferous     Continued.  Feet. 
A 1  adison  limestone — 
Limestone,  gray  to  white,  mostly  fine  grained,  rather  thick  bedded, 
locally  cherty  and  containing  some  fairly  thick  beds  of  chert ;  fos- 
siliferous 500 
Limestone,  fine  grained,  black  on  fresh  fracture,  blue-gray  on  weath- 
ered surface;  usually  flaggy,  contains  much  chert  as  irregular 
concretions;  fossiliferous;  locally  contains  a  bed  of  black  shale 
near  base 500 
Devono-Silurian: 
Jefferson  limestone:  Massive,  mostly  white,  but   with  many  blue-gray 
to  more  nearly  black  bods;   medium  grained 1,  000 
Yogo  limestone:  Gray  to  white,  medium  thick  bedded,  with  closely 
3paced,  thin,  siliceous  to  argillaceous  laminae*,  and  locally  a  little 
limestone  conglomerate,  overlain  by  flaggy  impure  limestone, 
calcareous  sandstone,  and  shale 100 
Dry  Creek  shale:  Near  Cable,  black  to  olive-green  shale  with  a  little 
gray-green,  line-grained  sandstone:  near  Philipsburg,  green  to 
white  banded  calcareous  shale 15-40 
Pilgrim  limestone:  Fine  grained,  hard,  usually  cream-white,  in  part 
very  light  gray,  locally  contains  thin  beds  of  shale 200 
Cambrian: 
Park   shale:  Calcareous,    light    olive-green  to   dark   purplish    brown, 
locally  banded,  very  thin  near  Princeton  and  Philipsburg 15-50 
Meagher  limestone:  Medium  thick  bedded,  prevailingly  medium 
grained,  light  blue-gray,  nearly  white  or  dark  gray  near  base, 
gritty  on  weathered  surface }()() 
Wolsey  shale:  Lower  pari  olive-green  to  black,  rather  fissile,  non- 
calcareous;  upper  pari  banded,  calcareous L00-300 
Flathead  quartzite:  Thick  bedded,  white  to  reddish,  of  medium  to 
coarse  texture 50  300 
Pre-1  Jambrian: 
Camp  Creek  formation:  Mostly  deep-red  shale,  with  some  green  in  thin 
layers,  grading  into  hard  quart zitic  reddish  to  white  sandstone, 
which  is  very  abundanl  in  upper  portion;  shallow-water  fea- 
tures   0-5,  000 
Blackfool  formation:  Calcareous  shale,  impure  limestone,  and  massive 
banded  calcareous  argillite.  dark  gray  to  light  greenish  gray  on 
fresh  fracture,  weathering  buff  or  yellow,  grading  into  purer 
gray-weathering  limestone,  which  occurs  generally  in  subordi- 
nate amount  interbedded  with  the  shale  in  thin  layers  and  as 
concretions 4,  000 
Ravalli  ( 7  >  formation:  Quartzite  overlain  by  purplish  and  greenish-gray 
siliceous  argillite 1,  000 
Prichard  (?)  formation:  Bluish-gray  argillites  largely  altered  to  mica 
schist,  with  interbedded  sandstone 2.  000  + 
All  the  sedimentary  rocks,  except  the  glacial  and  fluviatile  deposits, 
are  cut  by  granite  or  by  granite  porphyry.  The  granite  is  composed 
essentially  of  feldspar,  quartz,  mica,  and  hornblende.  One  large  body 
of  it  occurs  about  a  mile  east  of  Philipsburg,  the  western  contact 
passing  near  the  camps  of  Hasmark  and  Tower.  This  same  nias^ 
extends  southward  as  far  as  the  lied  Lion  mine  and  eastward  witliin 
