ncKEr,.] 
PORTLAND-CEMENT    RESOURCES    OF    NEW    YORK. 
523 
Point  itself.  It  appears  again  on  the  lake  shore  about  5  miles  south 
of  Westport,  near  Essex  village,  and  on  Willsboro  Point.  Its  most 
characteristic  and  extensive  outcrops,  however,  are  in  the  eastern  part 
of  Clinton  County.  It  is  shown  well  on  Valcour  Island,  and  on  Isle  la 
Motte,  where  it  has  been  extensively  quarried.  On  the  mainland  it 
occupies  large  areas  north  of  Valcour  and  west  of  Plattsburg,  where 
it  is  quarried.  The  largest  single  area  is  in  the  northeastern  part 
of  Clinton  County,  where  it  has  been  worked  extensively  for  lime 
and  building  stone.  This  area  extends  almost  without  a  break  from 
the  village  of  West  Chazy  to  the  lake  shore  and  northward  to  the 
Canadian  line  near  Rouse  Point. 
Local  details  concerning  the  distribution,  thickness,  etc.,  of  the 
Chazy  formation  will  be  found  in  a  paper  by  H.  P.  Cushing,  entitled 
"  Report  on  the  Geology  of  Clinton  County,"  in  the  Thirteenth  An- 
nual Report  of  the  New  York  State  Geologist,  pages  473-i90.  This 
paper  also  contains  geological  maps  of  the  county,  showing  the  area 
covered  by  the  limestone. 
COMPOSITION. 
The  Chazy  limestone  is  usually  a  very  pure  limestone,  low  in  both 
magnesia  and  clayey  matter.  It  is  commonly  bluish  to  grayish  in 
color,  and  has  a  slightly  crystalline  appearance.  Occasionally  it 
carries  notable  percentages  of  silica,  alumina,  etc.,  but  these  argil- 
laceous phases  are  rare.  Of  the  analyses  in  the  following  table,  Nos. 
1  and  2  represent  the  purest  type  of  the  Chazy  limestone,  while  Nos. 
3,  5,  and  6  contain  more  or  less  clayey  matter.  Analysis  No.  4  is 
included  as  representing  a  highly  argillaceous  type,  occurring  in  the 
same  area  as  Nos.  3,  5,  and  6 ;  but  this  particular  analysis  is  old  and 
of  doubtful  value. 
Analyses  of  Chazy  limestone,  New  York. 
Silica  (Si02) 
Almnina  (A1203) 
Iron  oxide  (FeX>:i)    . . 
Lime(CaO) 
Magnesia  (MgO) 
Carbon  dioxide  (C02) 
0.79 
.14 
.12 
54.36 
.67 
43.45 
0.72 
.39 
53.90 
1.44 
43. 92 
3. 
2.43 
.41 
51.00 
1.00 
n.d. 
21.39 
3.61 
39.37 
.52 
31.51 
4.40 
7.10 
3. 50 
44.35 
2.00 
37.05 
4.60 
4. 10 
1.90 
49.11 
.47 
39. 10 
1.  Chazy,  Clinton  County.     Rept.  New  York  State  Geologist  for  1897,  p.  433. 
2.  Chazy  Marble  Lime  Company,  Clinton  County.     D.  H.  Newland,  analyst.     Bull. 
York  State  Museum,  No.  44,  p.  755. 
3.  Willsboro  Point,  Essex  County.     T.  G.  White,  analyst.     Ibid.,  p.  782. 
4-G.  Willsboro  Point,  Essex  County.     E.  C.  Boynton,  analyst.     Ibid.,  pp.  782,  7s: 
New 
