NEW    BKUNSWICK,    NOVA    SCOTIA,    NEWFOUNDLAND,    ETC.       519 
the  southeastern  part  of  the  island,  including  the  peninsula  of 
Avalon,  are  pre-Cambrian  sedimentary  rocks,  basic  volcanics,  and 
various  intrusives.  The  sedimentary  group,  called  the  Avalon  group, 
consists  of  quartzites,  slate  conglomerates,  slates,  and  sandstones. 
These  are  gently  folded  and  slightly  metamorphosed  in  the  upper 
portions.  In  the  lower  part  of  the  group  basic  volcanics  and  various 
intrusives  are  abundant,  especially  on  the  west  side  of  the  peninsula 
of  Avalon  and  the  adjacent  portion  of  the  main  island,  the  folding 
is  closer,  and  metamorphism  is  correspondingly  great.  The  group 
was  found  by  Murray  to  be  more  than  11,000  feet  thick.  It  contains 
two  so-called  fossils,  Aspidella  terranovica  and  Arenicolites  spirales, 
but  these  have  been  held  by  Walcott  not  to  be  organic.  In  the 
Random  formation,  the  upper  member  of  the  Avalon  group,  Walcott 
found  annelid  trails. 
Howley  separates  from  the  Avalon  group  certain  of  the  highly 
metamorphosed  sediments  associated  with  the  basic  volcanics  near 
its  base,  and  calls  them  "  Huronian,"  a  term  which  Murray  originally 
applied  to  all  that  great  series  of  altered  sediments  and  partly 
volcanic  rocks  between  the  Laurentian  proper  and  the  lower  Cam- 
brian. Howley  provisionally  draws  the  line  between  the  Avalon 
and  the  "  Huronian  "  series  at  about  the  point  where  the  distinctly 
volcanic  rocks  cease  and  the  more  regular  sedimentary  strata  are  well 
defined.     No  unconformity  is  known  to  exist. 
From  Howley's  description  and  maps  (not  published),  and  from 
a  casual  examination  by  the  junior  author,  it  is  suggested  that  some 
so-called  "  Huronian  "  rocks  are  very  similar  in  some  of  their  aspects 
to  the  Keewatin  of  the  Lake  Superior  country. 
Overlying  the  Avalon  group  is  a  series  of  red  and  green  shales 
with  interbedded  limestones  of  Cambrian  age.  These  have  been 
correlated  by  Matthew  with  the  Etcheminian  group  of  New  Bruns- 
wick and  were  supposed  to  be  pre-Cambrian,  but  subsequent  work 
by  Walcott  showed  them  to  contain  Cambrian  fossils. 
The  Avalon  group  is  therefore  correlated  with  the  Algonkian.  The 
lower  metamorphosed  part,  with  the  basic  volcanics  (Howley's 
Huronian),  is  included.  There  is  a  possibility  that  this  part  should 
be  correlated  with  the  Keewatin,  though  no  unconformity  is  yet 
recognized  between  it  and  the  overlying  sedimentary  Avalon.  The 
relations  of  the  "Laurentian"  granites  and  gneisses  to  the  Avalon 
rocks  are  not  known,  although  some  of  them  are  certainly  intrusive. 
The  term  "Laurentian"  is  here  used  in  the  broader  sense  allowed  in 
the  recent  international  committee  report,  to  include  not  only  pre- 
Algonkian  rocks  but  unseparated  later  rocks. 
In  all  probability  the  Avalon  group,  as  explained  on  a  previous 
page,  is  equivalent  to  the  gold-bearing  quartzites  and  slates  of  south- 
eastern Nova  Scotia.     Both  of  these  may  be  equivalent  to  one  or  both 
