114  PRE-CAMBE1AN    GEOLOGY   OF    NORTH    AMERICA. 
the  Douglass  Houghton  Mining  Company's  land,  the  sandstone  dips 
southerly,  or  away  from  the  trap.  On  the  north  side  of  the  stream 
it  is  seen  resting  on  the  trap  in  large  blocks.  On  the  south  side  of 
Keweenaw  Point,  at  Bete  Grise  Bay,  the  sandstone  is  white  and  gran- 
ular, destitute  of  pebbles,  and  dips  southerly,  or  away  from  the  trap. 
In  the  bottom  of  the  bay,  when  the  water  is  calm,  the  bands  of  sand- 
stone can  be  seen  describing  immense  curves  parallel  to  the  direction 
of  the  Bohemian  range  of  mountains,  and  affording  conclusive  evi- 
dence that  their  bearing  and  upheaval  are  due  to  the  protrusion  of 
the  igneous  rocks.  On  the  east  side  of  sec.  14,  T.  59  N.,  R.  29  W.,  the 
sandstone  is  nearly  horizontal,  although  removed  but  a  few  miles  from 
the  trap. 
Burt,17  in  1850,  finds  on  Keweenaw  Point  and  along  the  south  shore 
of  Lake  Superior  to  the  mouth  of  Carp  River  and  in  the  Porcupine 
Mountains  five  principal  groups  of  rocks — Primary,  slates,  trap,  con- 
glomerate, and  sandstone.  With  the  Primary  rocks  are  placed  syenite 
and  granite.  Flanking  the  Primary  rocks  is  argillaceous  slate; 
flanking  (he  slates  and  resting  upon  them  are  red  and  variegated 
sandstones,  and  these  also  flank  the  Primary  rocks.  The  trap  rocks 
have  a  much  higher  angle  on  the  southeast  than  on  the  northwest  side 
of  tlie  range,  which  runs  from  the  northeast  end  of  Keweenaw  Point 
and  extends  in  a  course  generally  to  the  southwest.  The  conglomerate 
flanks  the  trap  range  on  the  northwest,  and  is  made  up  of  sand, 
pebbles,  and  small  bowlders  principally  derived  from  the  rocks  of 
the  trap  family.  Resting  conformably  upon  the  conglomerate  rock 
is  a  series  of  alternating  strata  of  sandstone  and  conglomerate. 
Hubbard,18  in  1850,  finds,  in  the  district  south  of  Lake  Superior, 
Primary  and  metamorphic  regions,  consisting  of  granite  rocks,  be- 
tween which  are  metamorphic  rocks  which  graduate  into  clay  slates. 
Burt,19  in  1850,  finds  the  area  bounded  on  the  north  by  the  fifth 
correction  line  and  south  by  the  fourth  correction  line  and  Brule 
River,  between  ranges  23  and  37,  granite  and  syenite,  talcose  and  ar- 
gillaceous slates,  greenstone  and  hornblende  slate,  mica  slates,  coarse 
sandstone,  calciferous  sand  rock,  encrinal  limestone,  red  sandstone 
and  red  clay,  and  magnetic  iron-ore  beds. 
Foster  and  Whitney,20  in  1850,  give  a  systematic  report  on  the 
geology  and  topography  of  the  copper  lands.  On  Keweenaw  Point 
these  consist  of  trappean  rocks  associated  with  conglomerates  and 
sandstones. 
On  this  point  are  two  trap  ranges,  the  southern  known  as  the  Bohe- 
mian Range.  The  conglomerates  are  volcanic  friction  rocks  rather 
than  the  result  of  erosion.  The  pebbles  may  have  received  their 
rounded  shape  by  being  projected  from  fissures  through  water.  The 
only  instance  in  the  district  in  which  trap  occurs  remote  from  the 
lines  of  fissure  is  in  the  northeast  corner  of  T.  49  N.,  R.  36  W.,  where 
