524  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  200. 
The  cost  of  fuel  in  the  Champlain  Valley  and  the  distance  from 
good  local  markets  will  probably  prevent  any  great  development  of 
the  cement  industry  in  the  Chazy  district,  though  the  limestone  itself 
is  well  adapted  to  cement  manufacture  and  good  clays  are  obtainable. 
TRENTON    LIMESTONE. 
DISTRIBUTION. 
The  Trenton  limestone,  including  the  Black  River  and  Birdseye,  or 
Lowville  limestone,  is  widely  distributed  throughout  New  York  State, 
appearing  in  the  valleys  of  Lake  Champlain,  upper  Hudson  River, 
Mohawk  River,  and  Black  River,  in  all  of  which  it  is  an  important 
quarry  stone.  It  occurs  also  in  the  southern  part  of  the  State,  but 
the  outcrops  in  that  district  are  so  small  and  scattered  that  they  may 
be  disregarded. 
Along  the  shores  of  Lake  Champlain  the  Trenton  limestone  is 
exposed  at  various  points,  being  quarried  more  or  less  extensively  on 
Isle  la  Motte,  at  Plattsburg,  and  on  Larabees  Point  and  Crown 
Point.  The  most  important  series  of  outcrops,  however,  are  along 
Mohawk  and  Black  rivers  and  in  the  vicinity  of  Glens  Falls. 
The  belt  which  is  quarried  near  Glens  Falls  enters  the  State  from 
Vermont,  in  northern  Washington  County,  and  passes  southward 
through  West  Haven  and  Whitehall,  close  to  the  line  of  the  Delaware 
and  Hudson  Railroad.  A  short  break  in  the  area  occurs  at  Fort  Ann, 
beyond  which  the  limestone  belt  passes  south  to  Sandy  Hill,  then  west 
to  Glens  Falls,  where  it  again  turns  south  to  Saratoga.  In  all  this 
distance  it  lies  close  to  the  railroads,  and  in  places  is  also  near  the 
canal.  It  is  extensively  quarried  for  Portland  cement  at  Glens  Falls 
and  for  lime  and  building  stone  at  Sandy  Hill,  Glens  Falls,  and 
other  points. 
In  the  lower  Mohawk  Valley  the  areas  covered  by  the  Trenton 
limestone  are  too  irregular  to  be  readily  described."  It  is  sufficient 
to  say  that  the  Trenton  outcrops  extensively  in  the  vicinity  of  Cranes- 
ville,  Amsterdam,  Tribes  Hill,  Yosts,  Sprakers,  Palatine  Bridge,  St. 
Johnsville,  Dolgeville,  and  Little  Falls.  It  is  quarried  at  many  of 
these  points  for  lime  or  building  stone.  It  should  be  noted,  however, 
that  another  limestone — the  Calciferous  or  Beekmantown  limestone — 
also  occurs  at  many  of  the  points  named,  underlying  the  Trenton 
limestone.  This  Calciferous  limestone,  however,  is  usually  a  very 
impure  rock,  high  in  magnesia,  and  should  therefore  be  carefully  dis- 
tinguished from  the  Trenton,  which  is  normally  very  low  in  magnesia. 
The  most  extensive  area  of  Trenton  limestone  in  the  State  remains  to 
be  described.     This  area  lies  mostly  in  Oneida,  Lewis,  and  Jefferson 
,fflThe  distribution  of  the  Trenton  limestone  throughout  much  of  its  range  in  the  Mo- 
hawk Valley  and  adjoining  regions  is  described  in  detail  in  a  paper  by  N.  II.  Darton  on 
the  "  Geology  of  the  Mohawk  Valley,"  published  in  the  Thirteenth  Annual  Report  of  the 
New  York  State  Geologist,  pp.  407-430. 
