Aan  hise.]  EASTERN    CANADA    AND    NEWFOUNDLAND.  251 
sula,  although  probably  later  than  Huronian,  as  the  former  is  never 
found  to  cut  the  Potsdam  sandstone. 
Walcott,77  in  1889,  corroborates  the  unconformity  between  the 
series  referred  by  Murray  to  the  Huroniau  and  the  overlying  series 
called  Potsdam.  This  latter  is  found  to  contain  the  Olenellus  fauna 
below  the  Paradoxides  and  is  placed  as  lower  Cambrian. 
SUMMARY   OF   RESULTS. 
The  reports  of  Jukes  and  Murray  are  far  more  complete  as  to  the 
geology  of  the  peninsula  of  Avalon  and  the  district  immediately  to  the 
west  than  they  are  of  the  great  northern  peninsula.  The  inap  of  this 
latter  area  is  greatly  generalized. 
The  unconformity  described  between  the  Upper  and  Lower  slate  of 
Jukes  is  evidently  the  same  as  that  found  by  Murray  between  his  Pots- 
dam and  Huronian.  The  Potsdam  was  later  determined  by  Walcott  to 
be  basal  Cambrian. 
It  is  perfectly  clear  that  in  Newfoundland,  and  particularly  in  Avalon 
and  southeastern  Newfoundland  proper,  is  a  great  series  of  fragmen- 
tal  rocks  unconformably  below  a  series  bearing  the  Olenellus  fauna. 
This  series  is  of  great  thickness,  probably  more  than  10,000  feet.  In 
certain  layers  it  carries  obscure  fossils  which,  according  to  Walcott,  are 
of  an  earlier  form  than  those  of  the  Cambrian.  It  then  follows  that  in 
this  region  we  have  a  pre-Cambrian  series  of  rocks  bearing  a  small  fauna 
of  a  rudimentary  type.  This  result  is  very  important  as  giving  a  start 
toward  a  fauna  which,  whatever  the  series  in  which  it  is  found  shall  be 
called,  is  greatly  older  than  that  now  recognized  as  basal  Cambrian. 
Whether  the  series  shall  be  called  Huronian,  as  is  done  by  Murray,  de- 
pends upon  the  definition  of  that  term.  If  all  pre-Cambrian  clastic 
series  are  to  be  placed  in  the  Huronian,  this  series  can  be  said  to  belong 
to  that  age,  but  if  only  those  rocks  are  to  be  here  placed  which  are  the 
equivalent  of  those  referred  to  that  term  on  the  north  shore  of  lake 
Huron,  we  have  as  yet  no  means  of  determining  whether  the  Newfound- 
land series  is  Huronian  or  not. 
The  relations  of  the  series  referred  to  the  Huronian  with  the  granites, 
gneisses  and  schists  which  are  placed  with  the  Lauren tian  are  far  less  sat- 
isfactorily known.  Nowhere  is  anything  said  as  to  any  structural  breaks 
between  these  two  series,  and  evidently  the  lines  between  the  so-called 
Laurentian  and  Huronian  are  based  upon  a  very  general  study.  Jukes, 
Murray  and  Howley  agree  that  in  Avalon  and  in  other  parts  of  Newfound- 
land arelarge  areas  of  eruptive  rocks,  including  both  basic  and  acidkinds, 
which  cut  the  various  sedimentaries.  Murray  does  not  find  that  the  Cam- 
brian of  Avalon  is  cut  by  granites  and  porphyries,  but,  according  to 
Jukes,  in  other  parts  of  Newfoundland  this  is  the  case.  However,  both 
basic  and  acid  eruptives,  including  granites,  syenites  and  porphyries, 
are  found  to  cut  in  the  most  intricate  manner  the  pre-Cambrian  sedimen- 
taries, and  as  a  result  of  this,  this  series  is  found  to  be  more  than  usually 
