216  PRE-CAMBRIAN    ROCKS    OF    NORTH    AMERICA.  Jbitll.86. 
constituting  the  rock  of  the  country  at  the  east  side  of  the  island  of 
North  Devon.  Between  capes  Osborne  and  Warrender  the  rocks  are 
graphic  granite,  which  passes  into  a  laminated  gneiss,  and  with  the 
gneiss  are  inter  stratified  beds  of  garnetiferous  mica- slate.  The  whole 
series  is  overlain  by  red  sandstones  of  banded  structure.  The  grani- 
toid rocks  are  again  found  on  the  north  side  of  the  island  of  North  Som- 
erset, where  they  form  the  eastern  boundary  of  Peel  sound.  Gape 
Granite  is  the  northern  boundary  of  the  granite.  On  Peel  sound  and 
Prince  of  Wales  island  is  a  dark  syenite  composed  of  feldspar  and 
hornblende.  This  rock  is  massive  and  eruptive  at  cape  M'Clure,  and 
occasionally  gneissic.  The  Silurian  of  the  Arctic  archipelago  rests 
everywhere  directly  on  the  granite,  with  a  sandstone,  passing  into  a 
coarse  grit,  at  its  base. 
Hatjghton,29  in  1859,  states  that  granitoid  rocks  everywhere  under- 
lie the  Arctic  archipelago.  At  Montreal  island  is  a  gneiss  which  exhib- 
its the  phenomena  of  foliation  in  a  marked  degree.  At  Eellot's  straits, 
in  latitude  72°  north,  are  found  gneissoid  granite,  graphic  granite,  and 
syenite.  At  Pond's  bay,  at  the  northern  extremity  of  Baffin  land, 
quartziferous  mica-schist  underlies  the  Silurian  limestone  and  is  inter- 
stratified  with  gneiss  and  garnetiferous  quartz  rock  inclining  38° 
WSW.  Cape  York,  on  the  Greenland  coast,  is  composed  of  fine 
grained  granite.  At  Wolstenholme  sound  the  granitoid  rocks  are  con- 
verted into  mica-slate  and  actinolite-slate,  the  two  rocks  passing  into 
each  other  by  almost  insensible  gradations.  Carey's  islands,  west  of 
Wolstenholme  sound,  are  composed  of  a  gneissose  mica-schist,  formed  of 
successive  layers  of  quartz  granules,  and  layers  of  jet-black  mica.  The 
mica-schist  passes  into  white  gneiss.  Yellow  and  white  sandstones  are 
also  found  in  small  quantity  upon  the  islands,  reposing  upon  the  gran- 
itoid rocks. 
Lieber,30  in  1860,  describes  on  the  coast  of  Labrador,  gneisses,  gran- 
ites, labradorites,  etc.,  at  various  localities. 
DeEance  and  Fielden,31  in  1878,  state  that  the  Laurentian  system 
is  the  fundamental  one  for  the  region  visited  by  Sir  George  Nares.  At 
cape  Eawson  is  an  important  overlying  series  which  occupies  the 
coast  of  Grinnell  land  from  Scoresby  bay  to  cape  Cresswell,  in  latitude 
82°  40'  north.  The  rocks  are  in  a  series  of  sharp  folds  with  a  general 
west-southwest  strike,  the  beds  being  often  vertical  and  frequently 
cleaved.  They  consist  of  jet-black  slates,  of  impure  limestones,  trav- 
ersed by  veins  of  quartz  and  cherts,  and  of  a  vast  series  of  quartzites 
and  grits.  They  are  compared  to  the  gold-bearing  series  of  Nova  Scotia 
and  doubtfully  referred  to  the  Huronian  system. 
Hind,32  in  1878,  describes  at  Mullens  cove,  in  the  Laurentian  series 
of  Labrador,  a  succession  of  interbedded  gneisses,  micaceous  schists, 
crystalline  limestones,  and  a  bed  of  calcareous  conglomerate.  The 
thickest  layer  of  white  crystalline  limestone  is  35  feet. 
Emerson,33  in  1879,  describes  the  rocks  of  Frobisher  bay,  collected 
