PORTLAND    CEMENT    MATERIALS    NEAR    DFRTTQTTE,  IOWA.        229 
Sections  made  at  the  other  three  places  are  as  follows : 
Section  of  Platteville-Galena  beds  near  Potosi  Station,  Wis. 
Ft.  in. 
6.  Limestone,  fine  grained,  thin  bedded  (Galena) ]2  0 
5.  Shale,  including  2  feet  4  inches  of  interbedded  limestone,  tola] .  7  10 
•1 .  Limesti >ne,  line  grained,  thin  bedded 3  P> 
3.  Limestone,  even  grained,  medium  bedded 3  0 
2.  Limestone,  crystalline,  thin  bedded 12  0 
1.  Limestone,  finegrained,  thin,  wavy  bedded  (partly  concealed  i.  L8  0 
Section  of  Platteville-Galena  beds  near  Waupeton,  Iain. 
Ft.  ii 
5.  Limestone,   sub  crystalline,   with    carbonaceous  shale  partings 
( <  ialena  i 12  0 
4.  Shale 0  1 
'A.    Limestone,  similar  to  No.  5 1  •"> 
2.  Shale,  blue,  including  7  inches  of  thin  limestone  partings,  total.  6  :'> 
1.  Limestone,  heavy  bedded 5  0 
Section  of  Platteville-Galena  beds  near  McCartney,  Wis. 
Ft.  in. 
6.  Limestone,  sub  crystalline,   with  carbonaceous    shale  partings 
(Galena) 12     0 
5.  Shale,  calcareous,  including  6  inches  of  thin  limestone  partings, 
total 3  6 
4.  Shale,  blue m 2  0 
Concealed 5  0 
3.  Limestone,  bluish,  crystalline,  thin  1  tedded 5  0 
Concealed 10  0 
2.  Limestone,  line  grained,  thin  bedded 7     0 
Concealed 13     0 
1.  Limestone,  heavy  bedded,  buff  to  blue,  probably  magnesian  . .     GO 
The  shale  beds,  exclusive  of  the  limestone  bands,  comprising  No.  5 
of  the  section  at  Potosi  Station,  No.  2,  at  Waupeton,  and  Nos.  4  and  5, 
at  McCartney,  were  analyzed  with  results  given  below: 
4  Analyses  of  shale  from  upper  division  of  Platteville  formation. 
[Analyst,  L.  G.  Michael,  Ames,  Iowa.] 
Potosi. 
Silica  (Si02) 
Alumina  ( A1203) 
Ferric  oxide  ( Fe203) 
Calcium  carbonate  (CaC03) . . . 
Magnesium  carbonate  (MgCO? 
Sulphur  trioxide  (S03) 
Alkalies,  as  K^O 
Combined  water 
Moisture 
4S  88 
14.54 
12.00 
8.58 
3.15 
L.26 
G.43 
4.48 
1.30 
Waupeton 
50.  69 
15.63 
4  83 
11.15 
8.  43 
2.65 
L.  46 
4.64 
McCartney. 
49.10 
17.15 
8.46 
11.04 
2.85 
1.  69 
3.  62 
5.  36 
.91 
For  cement  manufacture  all  these  shales  should  preferably  carry 
higher  percentages  of  silica  and  less  iron  oxide  in  order  that  the  ratio 
