van  hiss.]  EASTERN    CANADA    AND    NEWFOUNDLAND.  241 
brian  or  Huronian,  and  Laurentian.  The  Upper  Silurian  is  a  series  of 
argillites  estimated  at  9,000  feet  thick.  The  Lower  Silurian  consists  of 
micaceous,  schistose  and  corrugated  black  slates,  and  are  estimated  to 
have  a  thickness  of  from  12,000  to  15,000  feet.  The  gold-bearing  Silurian 
rocks  are  seen  to  rest  unconformably  on  a  gneissoid  series  between  Still- 
water and  Uniacke  station  on  the  Halifax  and  Windsor  railway,  and 
near  the  village  of  Sherbrooke,  in  Guysboro  county.  This  series  of 
Huronian  rocks  is  composed  of  beds  of  gneiss,  interstratified  with  mi- 
caceous schists,  schist-conglomerate,  beds  of  true  quartzite,  and  grits. 
The  gneiss  is  sometimes  porphyritic,  and  the  upper  beds  are  almost 
always  conglomeratic,  holding  pebbles  and  masses  of  schists,  grits,  and 
conglomerates,  which  are  iound  in  this  series.  This  older  series  rests 
unconformably  upon  the  Laurentian.  The  contacts  are  visible  on  the 
Windsor  and  Halifax  railway,  near  New  Stillwater  and  Mount  Uniacke 
stations.  The  gold-bearing  Silurian  strata  are  also  found  to  repose  un- 
conformably upon  the  Laurentian.  This  contact  is  also  observed  near 
Mount  Uniacke  station. 
Silliman,53  (year  unknown),  finds  that  the  gold-bearing  rocks  of  Nova 
Scotia  extend  along  the  Atlantic  coast  for  250  miles,  from  cape  Sable 
to  cape  Oanso.  These  rocks  are  hard,  slaty  ones,  which  are  sometimes 
micaceous  schists,  and  occasionally  granitic.  When  stratified  they  are 
always  found  standing  at  a  high  angle,  sometimes  almost  vertical,  and 
in  the  main  with  an  east  and  west  course.  The  zone  of  metamorphic 
rocks  varies  in  width  from  6  to  8  miles  at  its  eastern  extremity  to  40 
or  50  at  its  widest  part,  the  area  covered  being  about  6,000  square 
miles.  While  no  fossil  evidence  has  been  found  in  any  of  these  slates, 
opinion  seems  to  favor  the  belief  that  they  belong  to  the  Silurian  age, 
but  as  yet  no  place  has  been  found  where  the  rocks  next  higher  in  the 
geological  column  may  be  seen  resting  upon  them.  The  most  notice- 
able rock  of  the  gold  region  is  a  dark  gray  massive  rock,  resembling 
a  trap,  but  which  is  really  a  granular  quartzite.  It  has  three  well 
defined  planes  of  cleavage  by  which  it  breaks  into  very  irregularly 
shaped  masses.  This  rock  is  of  enormous  thickness,  and  is  undoubt- 
edly the  fundamental  or  basement  rock  of  the  region. 
Logan  and  Hartley,58  in  1870,  describe  felsites,  quartzites,  con- 
glomerates, and  slates,  adjacent  to  the  Pictou  coal  fields,  which  are 
pre-Carboniferous,  and  are  placed  as  probably  of  Devonian  age. 
Selwyn,54  in  1872,  in  studying  the  gold-bearing  slates,  agrees  with 
Dawson  that  they  belong  to  the  Primordial-Silurian  epoch.  As  evi- 
dence of  this  is  given  the  discovery  in  the  slates  of  Oven's  bluffs  of 
numerous  specimens  of  the  genus  Eophyton. 
The  granite  impresses  this  author  as  of  strictly  indigenous  character, 
and  neither  a  granitoid  gneissic  series  of  Laurentian  age  nor  an  intru- 
sive mass.  The  line  of  contact  with  the  Silurian  and  Devonian  leaves 
no  doubt  of  its  posterior  origin,  but  whether  intrusive  or  metamor- 
phic  in  situ  is  perhaps  uncertain. 
Bull.  86- 16 
