van  hise.]  EASTERN    UNITED    STATES.  377 
LITERATURE   OF   RHODE   ISLAND. 
Jackson,69  in  1840,  describes  the  older  roeks  of  Rhode  Island  as 
Primary  and  Metamorphic.  The  Primary  roeks  are  generally  said  to 
be  rocks  produced  in  the  stare  of  igneous  fusion.  Among  these  are 
placed  granite,  gniess  and  mica  slate,  although  it  is  doubtful  as  to  the 
manner  in  which  these  two  latter  rocks  were  formed.  At  Woonsocket 
a  conglomerate  passes  into  a  mica -slate.  In  general  the.  contact  be- 
tween the  gneiss,  mica-slate  and  graywacke  are  perfectly  sharp. 
Cozzens,70  in  1843,  finds  that  the  section  on  the  island  of  Rhode 
Island,  from  the  base  up,  includes  granite,  serpentine,  black  slate,  gray- 
wacke, black  slate,  Rhode  Island  coal  and  diluvium. 
Jackson,71  in  1859,  maintains  that  the  pebbles  of  the  Newport  con- 
glomerates in  their  present  condition  were  mechanically  formed  by  being 
roHed  upon  beaches,  often  the  distortions  and  indentations  being  ac- 
counted for  in  this  way. 
Hitchcock  (Ohas.  H.),72  in  1861,  describes  the  lower  rocks  of  the 
island  of  Aquidneck,  in  ascending  order,  as  (1)  talcoid  schists,  and 
conglomerates  with  red  jasper  pebbles;  (2)  the  Purgatory  conglomer- 
ate, the  pebbles  of  which  are  distorted;  (3)  mica-schists,  mica-slates, 
•conglomerates,  sandstones,  and  grits  west  of  Purgatory;  (4)  second 
conglomerate,  and  (5)  coal  measures. 
Dale,73  in  1883,  gives  detailed  sections  of  many  localities  and  de- 
scriptions of  various  places.  The  conglomerates  are  found  in  some 
cases  to  be  highly  metamorphic,  the  pebbles  being  unmistakably  elon- 
gated and  cut  with  scales  of  mica.  The  cleavage  of  the  pebbles  is 
regarded  as  partly  due  to  their  adhesion  to  the  cement.  The  fractures 
with  which  they  are  cut  is  possibly  due  to  wave  motion  or  to  the  con- 
traction of  the  conglomerate  in  cooling  from  a  heated  state.  The 
chronological  order  and  thickness  of  the  series  is  in  ascending  order  as 
follows : 
Feet. 
1.  Hornblende-schist  alternating  with  mica-schist 950 
2.  Chloritic  schists  and  associated  argillaceous  and  micaceous  schists £00-750 
3.  Greenish,  slaty  conglomerate,  with  argillaceous  and  siliceous  serpentine. 
(Conglomerate  I. ) 500 
4.  Quartz  and  clay,  aggregate 750 
5.  Argillaceous  schists  and  associated  slates,  etc 000 
G.  Quartzite  conglomerate,  with  grits  and  some  argillaceous  schist.     (Con  , 
glomerate  n. ) 750 
7.  Carbonaceous  schists  and  shales  with  argillaceous  schists 500 
8.  Fine  argillaceous  conglomerate  and  grit 500 
Total 5050-5300 
LITERATURE    OF    CONNECTICUT. 
Silliman,74  in  1820,  states  that  Primitive  rocks  occur  in  many  places 
in  the  counties  of  New  Haven  and  Litchfield.  These  rocks  succeed 
each  other  with  almost  precisely  the  arrangement  and  succession  laid 
