CLAYS  OF  CAPE  COD,  MASSACHUSETTS. 
By  Myron  L.  Fuller. 
:: 
INTRODUCTION. 
Area  treated. — In  the  present  paper  Cape  Cod  is  considered  as  synonymous  with  Barn 
stable  County,  all  the  land  south  and  east  of  Monument  River,  which  lacks  only  a  mil 
or  two  of  reaching  from  Massachusetts  Bay  to  Buzzards  Bay,  being  included  under  t 
term.     One  or  two  clay  localities  lying  a  short  distance  outside  of  the  limits  thus  defin 
are,  however,  mentioned. 
General  distribution  of  the  clays. — Although  the  clays  have  been  worked  at  relatively  fev 
points  on  the  cape,  they  underlie  a  considerable  portion  of  the  area  and  are  exposed  at  thtN 
surface  at  a  large  number  of  points,  especially  on  the  outer  arm  from  Highland  Light 
Truro,  to  Orleans  and  Chatham.  Westward  from  these  two  villages  the  clays  are  les; 
accessible,  though  still  encountered  in  shallow  wells  and  occasionally  exposed  in  the  lowei 
valleys  along  the  south  shore  and  in  the  bluffs  and  along  the  edges  of  the  marshes  on  the 
north  shore.  At  West  Barnstable,  however,  a  good  exposure,  worked  many  years  for  bricl 
clays,  is  found.  In  the  highlands,  marked  by  the  morainal  ridge  and  sandy-wash  plain 
lying  between  the  north  and  south  shores  of  this  part  of  the  cape  and  east  of  BuzzarJ 
Bay.  the  clays  are  too  deep  beneath  the  surface  to  ever  be  economically  available.  Along 
the  shore  of  Buzzards  Bay  no  important  clays  have  yet  been  found,  and  it  is  probablci 
that  they  are  here  below  sea  level. 
Field  work. — The  data  relating  to  the  Cape  Cod  clays  were  collected  in  connection  with 
a  study  of  the  Pleistocene  geology  and  artesian  water  resources  of  southeastern  New  Eng- 
land. As  a  part  of  this  investigation  it  became  necessary  to  trace  out  the  clay  beds  oi 
the  region,  during  which  abundant  opportunity  to  note  their  economic  aspects  was  pre- 
sented. The  study  was  made  in  1904  and  1905,  and  during  the  latter  year  the  writer  had 
associated  with  him  Mr.  F.  G.  Clapp,  to  whom  credit  for  a  material  portion  of  the  facts 
is  due. 
GEOLOGY. 
General  features. — Cape  Cod  is  composed  entirely  of  clay,  sand,  and  gravel,  with  occa- 
sionally a  bed  of  till,  consisting  of  a  heterogeneous  mixture  of  clay,  sand,  and  bowlders, 
often  known  locally  as  hardpan,  and  a  superficial  deposit  of  scattered  bowlders,  some- 
times of  large  size.  Bed  rock  is  not  encountered  anywhere  on  the  cape,  but  is  relatively 
close  to  the  surface  near  the  head  of  Buzzards  Bay,  where  wells  about  Onset  are  said  to 
have  encountered  it  at  a  depth  of  from  60  to  100  feet. 
Superficially,  the  backbone  of  the  cape,  except  the  outer  arm,  appears  morainal.  Start- 
ing at  Woods  Hole  and  extending  northward  along  the  shore  of  Buzzards  Bay  to  Monu- 
ment River  is  a  hummocky  and  frequently  bowlder-covered  ridge,  with  here  and  there  an 
undrained  depression  or  kettle,  often  containing  a  pond  of  more  or  less  size.  Near  Monu- 
ment River  the  ridge  bends  at  a  somewhat  sharp  angle  to  the  southeast,  following  the 
shore  of  Cape  Cod  Bay  to  the  vicinity  of  Orleans,  where  it  crosses  the  outer  arm  and  is  cut 
off  by  the  sea.  To  the  east  of  the  Buzzards  Bay  portion  and  to  the  south  of  the  remainder 
of  the  ridge  lies  a  great  flat  sandy-wash  plain  sloping  gently  to  the  sea.  North  of  Orleans 
the  outer  arm  consists  superficially  at  least  of  fine  gravels  and  sandy  plains,  which  are 
horizontally  stratified  in  Eastham,  but  are  more  irregular  in  structure  and  surface  topog- 
raphy in  the  Wellfleet  and  Truro  regions.  At  the  end  of  the  cape,  in  the  vicinity  of  Prov- 
incetown,  nothing  but  sands  thrown  up  by  the  waves  or  piled  up  by  the  winds  as  dunes 
are  to  be  seen. 
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