vanhisb.]  EASTERN    ONTARIO    AND    WESTERN    QUEBEC.  27 
lake  limestone,  20  feet;  orthoclase-gneiss,  including  quartzite,  3,400 
feet;  anorthosite,  thickness  (wholly  conjectural),  10,000  feet;  total, 
32,750  feet.  In  the  limestones  are  fossil-like  forms  which  resemble 
Stromatojwra  rugosa.  Accompanying  the  account  of  the  Laurentian  is 
a  detailed  map  of  it  in  parts  of  the  counties  of  Terrebonne,  Argentenil, 
and  Two  Mountains. 
The  anorthosite  probably  overlies  the  Grenville  series  uncomformably. 
It  is  remarked  that  if  the  two  inferior  limestone  bands  of  the  Gren- 
ville series  disappear  on  reaching  the  margin  of  the  anorthosite,  it  is 
conclusive  evidence  of  the  existence  in  the  Laurentian  system  of  two 
immense  sedimentary  formations,  the  one  superimposed  unconformably 
upou  the  other,  with  probably  a  great  difference  of  time  between  them. 
Logan,12  in  1863,  first  describes  a  part  of  what  was  later  called  the 
Hastings  series.  In  ascending  order  are  found  contorted  gneiss  and 
micaceous  schists  cut  by  red  syenite  veins.  Above  this  comes  crys- 
talline limestone,  and  north  of  the  village  of  Madoc,  still  in  ascending 
order,  occurs  a  somewhat  micaceous  schist,  Avhich  contains  numerous 
fragments  of  rock  in  character  different  from  the  matrix,  some  of  them 
resembling  syenite  or  greenstone.  The  pebbles  are  in  places  distinctly 
rounded. 
BiGSBY,13  in  1864,  states  that  crystalline  limestones  occur  in  bands 
from  50  to  1,500  feet  thick  at  Gananoque,  on  the  lake  of  the  Thousand 
isles,  and  on  the  Mattawa.  The  bands  of  marble  are  tortuous,  and 
between  them  are  sometimes  found  corrugated  seams  of  gneiss.  Con- 
glomerates and  grits  occur  at  Bastard,  on  the  Ottawa,  and  at  Madoc,  near 
lake  Ontario.  At  the  former  place,  between  the  beds  of  marble,  is 
quartzose  sandstone,  with  pebbles  of  calcareous  sandstone  and  vitrified 
quartz.  At  Madoc  village  are  inter  stratified  marble  and  conglomerate, 
one  being  bluish  micaceous  schist,  holding  fragments  of  greenstone  and 
syenite,  the  other  being  a  dolomite  with  large  pebbles  of  quartz,  feld- 
spar, and  calcite.  As  proofs  of  life  are  the  occurrence  of  limestone, 
carbon,  phosphorus,  sulphur,  and  iron  ore.  The  Laurentian  system  as 
a  whole  consists  of,  (1)  orthoclase-gneiss,  sometimes  granitoid,  with 
quartzite,  hornblendic  and  micaceous  schists,  pyroxene,  and  garnet 
rock;  (2)  white  crystalline  limestone  and  dolomites,  in  numerous  thick 
beds,  containing  serpentine,  pyroxene,  hornblende,  mica,  graphite,  iron 
ores,  apatite,  fluor,  etc.,  and  interstratified  with  bands  of  gneiss;  (3) 
lime -feldspar  rock,  or  anorthosite,  containing  hypersthene,  ilmenite, 
pyroxene,  horneblende,  graphite,  etc.  These  three  groups  are  traversed 
by  granitic  and  metalliferous  veins. 
Macfarlane,14  in  1866,  describes  the  Laurentian  rocks  of  several 
towns  in  the  county  of  Hastings.  The  rocks  here  found  include  granite, 
granite-gneiss,  gneiss,  petrosilex,  conglomerates,  and  limestones.  At 
Madoc  are  conglomerates  consisting  of  pebbles,  generally  of  quartzite, 
in  a  schistose  matrix,  lithologically  not  unlike  some  of  the  Huronian 
rocks. 
