Skip to main content

Full text of "Recent development in Illinois with discussion of producing formations below McClosky "sand""

See other formats


Press  Bulletin  Series  For  The  Oil  and  Gas  Industry 

STATE  OF  ILLINOIS 

HENRY  HORNER,  Governor 

DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

JOHN  J.  HALLIHAN,  Director 

DIVISION  OF  THE 

STATE    GEOLOGICAL    SURVEY 

M.  M.  LEIGHTON,  Chief,  Urbana 

No.  34  ILLINOIS  PETROLEUM  July  lo,  1939 

RECENT  DEVELOPMENT  IN  ILLINOIS  WITH 

DISCUSSION  OF  PRODUCING  FORMATIONS 

BELOW  McCLOSKY  "SAND"i 

ALFRED  H.  BELL  and  GEORGE  V.  COHEE 

Urbana,  Illinois 

ABSTRACT 

The  recent  discovery  of  Devonian  oil  production  in  the  old  Sandoval  field  has 
focused  attention  on  Devonian  possibilities  in  the  Illinois  basin.  As  yet  there  has  been 
relatively  little  testing  of  pre-Ste.  Genevieve  formations  in  the  region.  This  paper 
reviews  the  known  occurrences  in  Illinois  of  oil  in  the  Mississippian  below  the  Ste. 
Genevieve  and  in  the  Devonian,  Silurian,  and  Ordovician  systems. 

A  brief  statement  regarding  developments  in  Illinois  during  1938  and  up  to  the 
early  part  of  March,  1939,  is  included. 

INTRODUCTION 

During  the  12-month  period  from  March  i,  1938  to  March  i,  1939, 
the  rate  of  oil  production  in  Illinois  has  mounted  rapidly  from  a  daily 
average  of  43,000  barrels  to  one  of  160,000  barrels — nearly  a  4-fold 
increase.  This  increase  has  been  due  almost  entirely  to  the  develop- 
ment of  fields  on  the  western  side  of  the  Illinois  basin,  producing 
from  sandstones  in  the  lower  part  of  the  Chester  (Upper  Mississip- 
pian) series.  The  previous  development  during  1937  had  been  mainly 
in  the  central  part  of  the  basin  where  production  to  date  is  nearly 
all  from  the  Ste.  Genevieve  oolitic  limestone  (McClosky  "sand")  in 
the  upper  part  of  the  Iowa  (Lower  Mississippian)  series. 

A  discovery  which  may  have  much  significance  in  future  develop- 
ment was  made  in  December,  1938,  when  oil  production  was  obtained 
in  Devonian  limestone  in  the  old  Sandoval  field  of  Marion  County, 
Illinois,  which  had  been  producing  for  30  years  from  the  Benoist 
sand  of  the  Chester  series.  This  article  includes  a  discussion  of  de- 
velopments during  the  12-month  period,  and  a  review  of  the  known 
occurrences  of  oil  in  Illinois  in  strata  below  the  McClosky. 

DEVELOPMENT  IN  1938 

An  index  map  of  new  fields  and  extensions  discovered  during  1938 
and  the  first  2  months  of  1939  is  shown  in  Figure  i. 

In  the  last  two  years  23  new  pools  were  discovered  in  Illinois,  8 

in  1937  and  15  in  1938.  Four  new  pools  were  discovered  during  the 

first  two  months  of  1939.  Following  the  presentation  of  the  paper  at 

the  annual  meeting  of  the  Association  three  additional  pools  were 

discovered  to  April  4. 

1  Read  before  the  Association  at  Oklahoma  City,  March  23,  1939.  Manuscript  re- 
ceived, April  15,  1939.  Reprinted  from  Bull.  .\m.  Assoc.  Petr.  Geol.,  Vol.  23,  pp.  807- 
822,  1939. 

807 


8o8 


ALFRED  H.  BELL  AND  GEORGE  V.  COHEE 


With  the  new  development  in  the  state  production  has  been  ob- 
tained from  three  formations  which  were  not  productive  in  the  old 
fields.  A  sandstone  in  the  Paint  Creek  formation  is  productive  in  the 
Louden  (Beecher  City)  pool.  It  has  locally  been  called  the  "Stray" 
sand.  The  Aux  Vases  sandstone,  the  basal  formation  of  the  Chester 


LEGEND 
©    1939    DISCOVERIES 

#    l9Se   DISCOVERIES  4    EXTENSONS 
O    ^31    DISCOVERIES 
@   OLD    FIELDS 


SCAL£  OF  UIL£S 


ILLINOIS  STATE   CEOLOeiCAL    SURVBr 
APRIL  4.  19)9 


Fig.  I. — Index  map  showing  old  and  new  oil  and  gas  fields  in  Illinois.  The  new 
fields  are  as  follows:  (i)  Sorento;  (2)  Cordes;  (3)  Louden  (Beecher  City);  (4)  St.  James; 
(s)  Patoka;  (6)  Centralia;  (7)  Salem  (Lake  Centralia);  (8)  Dix;  (9)  Roaches;  (10) 
Marcoe;  (11)  Elk  Prairie;  (12)  Ina;  (13)  Mattoon;  (14)  Stewardson;  (15)  Tola;  (16) 
Flora;  (17)  Clay  City;  (18)  Rinard;  (19)  Enterprise;  (20)  Cisne;  (21)  Mt.  Erie;  (22) 
Boyleston;  (23)  North  Aden;  (24)  Aden;  (25)  Barnhill;  (26)  Golden  Gate;  (27)  Leech 
Township;  (28)  Olney;  (29)  Noble;  (30)  Schnell;  (31)  Russellville  gas.  Numbers  16  to 
30  inclusive  are  referred  to  collectively  as  the  Central  Basin  fields. 

series,  is  productive  in  the  Salem  (Lake  Centralia)  and  Cisne  pools 
and  in  the  recently  discovered  lola  pool.  The  Rosiclare  sandstone 
member  of  the  Ste.  Genevieve  formation  is  productive  in  the  Roaches 
pool  in  west-central  Jefferson  County.  Tables  I  and  II  list  the  produc- 
ing strata  in  the  state  and  the  approximate  depths  to  the  producing 
formations  in  the  new  fields. 

The  course  of  development  in  this  14-month  period  in  four  pro- 
ducing areas,  which  include  about  97  per  cent  of  the  production  from 


ILLINOIS  STATE  GEOLOGICAL  SURVEY 


3  3051  00005  0934 


RECENT  DEVELOPMENT  IN  ILLINOIS 


809 


LEGEND 
o— —  NUMBER    OF    WELLS       PRODUCING 

o AVERAGE     PRODUCTION    PER    WELL     PER      DAY 

VyMOi    DAILY     AVERAGE      PRODUCTION    BY     MONTHS 


ILLINOIS    STATE    GEOLOGICAL     SURVEY 


Fig.  2. — Oil  production  and  number  of  producing  wells  in  four  new 
producing  areas  of  Illinois,  January,  1938-February,  1939. 


8io    ALFRED  H.  BELL  AND  GEORGE  V.  COHEE 

the  new  fields,  is  shown  by  Figure  2.  For  each  of  the  four  areas  three 
sets  of  data  are  shown  graphically:  (i)  the  number  of  producing  wells 
at  the  end  of  each  month;  (2)  the  daily  average  production  by  the 
month;  and  (3)  the  daily  average  production  per  well  each  month. 

The  data  for  this  last  curve  were  calculated  by  dividing  the  daily 
average  production  for  each  month  and  for  each  field  by  the  number 
of  producing  wells  in  the  field  at  the  end  of  the  month.  This  involves 
an  error  which  is  small  in  comparison  with  the  figure  obtained  but 
the  results  are  useful  as  an  indication  of  the  trend  in  average  produc- 
tion per  well  in  each  area. 

There  is  an  upward  trend  in  the  total  production  rate  of  the  new 
fields  during  the  14-month  period,  an  increase  each  month  in  the 
number  of  producing  wells,  and  a  generally  downward  trend  in  the 
average  production  per  well. 

The  upper  three  graphs  are  of  fields  producing  almost  entirely 
from  sandstone,  and  the  lowermost  graph  is  a  composite  of  fields 
producing  almost  entirely  from  limestone. 

The  central  basin  fields,  producing  from  limestone,  had  their 
initial  development  in  the  spring  of  1937,  previous  to  the  period  of 
the  graph,  and  their  daily  production  had  already  reached  21,000 
barrels,  from  126  wells.  During  most  of  the  period  of  the  graph  the 
flush  production  of  the  new  wells  was  hardly  more  than  sufficient  to 
off'set  the  decline  of  the  previous  wells.  This  was  interrupted  in 
August,  September,  and  October,  1938,  when  the  North  Aden  field, 
Wayne  County,  was  being  developed.  The  trend  of  the  average  pro- 
duction per  well  has  been  downward  during  most  of  the  period  from 
a  high  of  148  barrels  to  a  low  of  52  barrels.  There  was  very  little 
artificial  restriction  of  production  in  this  area  during  the  period  of 
the  graph 

Of  the  three  areas  producing  from  sandstone  for  which  graphs  are 
shown,  the  earliest  to  be  developed  was  the  Centralia  (New).  Pipe- 
line proration  was  introduced  in  this  pool  in  April,  1938,  and  has  been 
in  force  in  varying  degree  ever  since.  Because  this  field  is  located 
partly  within  the  city  limits  of  Centralia,  there  was  very  rapid  drill- 
ing development,  and  a  peak  of  production  was  reached  in  August, 
1938.  The  rate  of  production  declined  for  the  following  6  months. 
The  close  spacing  of  the  wells  in  part  of  the  area  within  the  city 
limits  is  already  leading  to  early  abandonment  of  some  of  them. 

The  Louden  (Beecher  City)  field,  Fayette  County,  had  a  rather 
slow  development  up  to  August,  1938,  after  which  the  rate  of  drilling 
and  the  daily  production  increased  rapidly.  The  rate  of  drilling  was 
retarded  somewhat  in  January  and  February,  but  the  production 


RECENT  DEVELOPMENT  IN  ILLINOIS  8ii 

continued  to  increase,  and  the  average  production  per  well  rose 
slightly.  Because  pipe-line  proration  has  been  in  effect  in  this  field 
from  the  beginning  the  curve  of  the  average  production  per  well 
can  not  be  regarded  as  representing  natural  conditions. 

The  Salem  (Lake  Centralia)  field  is  outstanding  among  the  new 
fields  of  Illinois.  At  the  end  of  the  period  of  the  graph  (February  28, 
1939)  it  was  producing  more  than  half  of  the  total  oil  of  the  state. 
When  it  is  remembered  that  the  discovery  well  of  the  field  was  com- 
pleted July  6,  1938,  the  exceptionally  rapid  development  is  apparent. 
The  curve  representing  number  of  wells  by  months  is  seen  to  be  the 
steepest  of  the  four  areas  represented.  At  the  end  of  February,  1939, 
there  were  676  wells  producing  a  daily  average  for  February  of  ap- 
proximately 78,000  barrels,  or  an  average  of  115  barrels  per  well  per 
day.  The  curve  representing  daily  average  production  per  well  does 
not  show  an  overall  downward  trend;  on  the  contrary  it  shows  a 
rise  during  the  last  5  months  represented  in  the  graph.  Pipe-line 
proration  in  varying  amounts  has  been  in  effect  almost  from  the 
beginning. 

Principal  development  to  date  in  the  Salem  field  has  been  in 
the  Benoist  sand  (Chester  series).  However,  two  other  formations, 
the  Aux  Vases  in  the  Chester  and  the  McClosky,  are  yielding  some 
production  and  may  be  productive  over  most  if  not  all  of  the  area  of 
Benoist  production.  The  possibilities  of  production  below  the  Mc- 
Closky in  this  area  remain  to  be  explored. 

PRE-MCCLOSKY  PRODUCTION 

With  the  widespread  development  in  Illinois  attention  has  been 
focused  upon  the  potential  oil  strata  below  the  McClosky  "sand."  To 
date  the  development  in  Illinois  has  been  largely  limited  to  the 
McClosky  and  higher  formations  because  of  the  cost  of  deeper  explor- 
ation and  the  small  amount  of  structural  information  regarding  the 
lower  formations.  Production  has  been  obtained  from  strata  below 
the  McClosky  in  various  areas  in  Illinois.  A  discussion  of  these  areas 
follows. 

A  well,  recently  drilled  to  the  Devonian  in  the  Sandoval  field, 
Marion  County,  created  much  interest  in  Devonian-Silurian  possi- 
bilities in  other  areas  in  the  state.  The  well  was  drilled  on  the  crest  of 
the  dome  and  reached  the  Devonian  limestone  at  a  depth  of  2,876 
feet,  producing  from  2,920  to  2,926  feet.  A  second  well,  a  dry  hole, 
was  drilled  to  the  Devonian  at  the  northeastern  edge  of  the  old  pro- 
ductive area  and  found  the  top  of  the  Devonian  125  feet  lower  than 
in  the  discovery  well  one-half  mile  southwest.  A  third  well  which  was 


TABLE  I 

Oil  and  Gas  PRODUcrac  Strata  in  Illinois 


System  or  Series 


Pleistocene 


Pennsylvanlan 


Chester 

(Upper  Mlaslselpplan) 

Series 


Formation  and  Llthology* 


McLeansboro  -  sh.,  ss.,  thin  la., 
and  coal 


Carbondale  -  sh. ,  Is.,  ss.,  coal- 


PottSTllle  -  SB.,  sh.,  and  thin  coal 


Local  Name  and  Area  Productive 


Gas  from  glacial  drift 


Klnkald  -  Is. ,  sh. 
Degonla  -  ss. 
Clore  -  Is. ,  sh. 
Palestine  -  ss. 
Menard  -  Is. ,  sh. 
Waltersburg  -  bs. 
Vienna  -  le. ,  sh. 
Tar  Springs  -  ss. 
Glen  Dean  -  Is.,  sh. 
Hardlnsburg  -  ss. 
Golconda  -  Is.,  eh. 
Cypress  -  bs. 


Paint  Creek  -  Is.,  sh. 
Bethel  -  ss.  


Renault  -  Is.,  sh. ,  ss 
Aui  Vases  -  ss.  


Upper  Slgglns,  "Gas"  -  Clark  County  fields 

Casey,  Claypool,  Upper  Partlow,  Lower 

Slgglns,  "Bellalr  500"  -  Clark  County 
Dykstra,  Wilson  -  Marion  County 

Lower  Partlow  -  Clark  Coimty 
Robinson  -  Crawford  County 
Bridgeport  -  Lawrence  County 
Buchanan  -  Lawrence  County 
Blehl  Se  Jordan  -  Wabash  County 
Petro  -  Marion  County 


jCarlyle  -  Clinton  County 
iKlrkwood  -  Lawrence  County 
I  Upper  Llndley  -  Bond  County 
Iweller  -  Richland  and  Fayette  Counties 
-Stray  -  Fayette  County 
[Tracey  -  Lavrenoe  County 
iBenolst  -  Clinton,  Fayette,  Jefferson 
and  Marlon  Counties 

(Aux  Vases  -  Marlon  County 
Bradley  -  Wayne  County 


Ste.  Genevieve  -  Is. 


Iowa 

(Lower  Mlsslsslppian) 

Series 


,:  "t 


Levlas  -  la. 
Rosl Clare  -  ss. 
Fredonla  -  Is.  . 


St.  Louis 
Salem  -  Is. 
Waj"saw  -  Is. 
Xeokuk  -  Is. 
Burlington  -  Is. 
Fern  Glen  -  Is. 


Osage  group 


Klnderhook  -  sh. ,  la.,  ss. 


■Roslclare  -  Jefferson  County 
-McClosky  "sand"  -  Illinois  basin  and 
southeastern  fields 

•Westfleld  lime  -  Clark  County 

-"Mississippi  Lime" 

■Carper  sand  -  Clark  County 


Misalsslpplan 
and  Devonian 


Chattanooga  - 
New  Albany  sh. 


Devonian 


Limestone 


Silurian 


Dolomite 


"Nlagaran"  Martinsville  pool  -  Clark  County 
"Holng  sand"  Colmar -Plymouth  field  - 
McDonough  County 


-(Hunton  limestone  of  Oklahoma") - 


Ordoviclan 


Maquoketa  -  sh. 
Klmmswlck  -  Is.- 
Plattln  -  Is. 
Joachim  -  Is. 
St.  Peter  -  as.. 


"Trenton"  Westfleld  pool  -  Clark  County 
Dupo  field  -  St.  Clair  County 

(viola  limestone  of  Oklahoma) 

(Wilcoi  Band  of  Oklahoma) 


•Is.  -  limestone;  ss.  -  sandstone;  ah.  -  shale 


Q 

s 


O 
N 

s 

o 

w 

pa 


Q 
O 
« 

PL, 

< 

& 

U 
2 

(In 


W 
H 
pit 

H 

Q 

M 
H 
< 

o 


o 

o 

c 

c: 

1 

?s 

Tf 

rH 

8 

rH 

■S  ^  ;^ 

2i 

1 

to 

1 

(D    - 

p. 

5S 

8 

:g- 

rH    +i    Q 

5 

§"8 

V  o 

§ 

ll 

s-l 

o  e  o 
•H  (8  r- 

O    to   rH 

OS 

S|8 

3 

,a 

S 

w 

& 

s 

O 

O 

E 

w 

K 

TJ 

oS'OUNrHt-ajONrH   lA 
a\CT\0    OONrHOJ    K>J- 

C 

t 

OJOJ  fr\H^OJK>rr\rrvrfN 

0) 

03 

^8 

©  CK 

-H                    rH                             C    f» 

©  vO 

rH    0\ 

^  ai 

Tb    CVJ 

O                    rH                             © 

d 

d 

©     >)   ©    d    d          Tl   J3 

t^ 

4 

L< 

t.>rH    d     C    t,     C     C   •§     O 

4^ 

» 

m 

&  X^    C   Si    o    m    ^           © 

c 

rHOrHOrH-rt-cl        •© 

o 

oeoraf.;,o<B:fj 

ptTBB    XjtSOXOOW 

>> 

-p 

tj 

■rH  a 

c 

o  © 

d 

•4J 

TJ 

CO    - 

m  . 

s^  :3 

o 

^  O 

53 

U    -H 

O  J 

d  ITN 

c  m 

o 

»    rH 

O     1 

p^ 

0) 

d 

m 

* 

CD 

0) 

§ 

feo 

•-J 

C    rH 

+J 

n 

CO 

CO 

+j 

J4 

o   - 

o 

■rH    O 

■^ 

O   CU 

d 

c  ^ 

(^ 

d  r-< 

-p 

•n  O 

M 

O  lf\ 

C  O 

O 

d  r^ 

«) 

fH 

m 

>= 

e 

•p 

d 

j?r     - 

(<  e 

(D    - 

o  - 

o  <d  o 

■P    o 

•n  O 

d  o 

o  c  o 

C    rH 

O  [^ 

^S 

t>   0 

C  f- 

o  m  oj 

o  to 

©  r^ 

3^ 

o  = 

m 

2 

e    1 

< 

X 

3 

d 

m 

■p 

»H 

tD    - 

d 

o  o 

o  R 

u 

u  o 

•p 

c 

ea 

C  K^ 

o 

o 

m 

o 

tJ 

C 

1    o 

m 

o  m 

(0 

^    rH 

>>  o 

a>  o 

rH    +^ 

iH   O 

^^ 

fH  ^ 

O  (0 

o 

o 

Pi 

4->    - 

s 

c  o 

p 

•ct 

1  fl 

c 

cd 

d   :3 

01   - 

o 

o  i. 

l^ 

o  >-< 

PH 

o 

m 

Ic 

o 

d 

■*->  o 

CO 

rH 

d 

•r) 

(Q   ^ 

s> 

CO 

O 

c 

(>»+J 

o 

a 

d 

o 

5 

CO     £ 

iH 

u 

*3 

>■ 

Id 

^i 

> 
(0 

d 

g 

d 

M 

o 

4J 

o 

<: 

o 

1 

§ 

a 

a^seqo 

9A8;Aeuao   'S'js 

o 

HVmVA'USfUQd 

MVIddl 

SSISSIW 

8i4 


ALFRED  H.  BELL  AND  GEORGE  V.  COHEE 


also  dry  was  drilled  \  mile  west  of  the  first  well  and  the  top  of  the 
Devonian  limestone  was  found  to  be  75  feet  lower. 

Evidently,  there  was  little  or  no  shifting  of  the  structure  with 
depth.  Also,  the  structure  becomes  sharper  with  depth  and  has  a 


APftlL  4.  /0J9 


I.  CLARK  CO.  (OLD    FIELDS) 


ST  LOUIS 

SALEI 

DEVON 

TRENTON" 
ST. LOUIS 
ST  LOUIS 

-  DEVONIAN 

-  "TRENTON" 

-  DEVONIAN  - 

-  DEVONIAN 

-  SILURIAN 

-  DEVONIAN 


a.  LAWRENCE  CO.(OL0  FIELDS) 
2.   INA 

4  SANDOVAL 

5  DUPO   AND   WATERLOO 
e     COLLIN5VILL6 
T      SORENTO 
a     PIKE  COUNTY   CAS 
9  ,  COLMAR  -  PLYMOUTH 
10.  JACKSONVILLE   CAS 
n. DECATUR 
l£  HERSCHER 


»  PRODUCTION   BELOW  MC  CLOSKY        OOLD   FIELD        O  NEW   FIELI 


ILLINOIS  STATE  GEOLOGICAL  SURVEY 


Fig.  3. — Index  map  of  areas  of  production  from  formations  below 
McClosky  (Ste.  Genevieve  formation,  Lower  IMississippian). 


smaller  area  of  production  than  the  overlying  Bethel  sandstone.  It 
is  believed  that  similar  structural  conditions  will  be  found  on  other 
structures  in  the  Illinois  basin. 

The  discovery  well  of  the  Louden  (Beecher  City)  field,  the  Carter 
Oil  Company's  Mary  Miller  No.  i,  Sec.  12,  T.  8  N.,  R.  3  E.,  first 
produced  oil  from  the  Devonian,  but  since  the  production  was  very 


RECENT  DEVELOPMENT  IN  ILLINOIS  815 

small,  it  was  plugged  back  to  the  Cypress  sandstone  from  which  it 
is  now  producing.  The  well  is  located  at  the  northeastern  edge  of  the 
structure  and  is  within  the  area  of  production  of  the  overlying 
Chester  formation. 

Another  well  to  the  Devonian  was  drilled  about  the  same  time  as 
the  Sandoval  discovery.  The  DeMayo  et  al.  Dressor  No.  i,  Sec.  21, 
T.  6  N.,  R.  4  W.,  Bond  County,  drilled  on  the  flank  of  the  Sorento 
dome,  made  a  small  producer  in  the  upper  part  of  the  Devonian  from 
1,800  to  1,830  feet.  The  well  was  drilled  higher  on  structure  and  about 
\  mile  north  of  an  old  well  which  had  a  good  showing  of  oil  in  the 
same  zone.  Owing  to  unfavorable  weather  and  road  conditions  there 
has  been  no  further  development  in  this  area.  It  is  expected  that  this 
discovery  will  stimulate  interest  in  western  Illinois. 

Production  in  the  Lower  Mississippian  below  the  McClosky  is 
practically  limited  to  areas  in  which  there  is  a  marked  erosional 
unconformity  at  the  top  of  the  Lower  Mississippian.  However,  there 
are  a  few  exceptions  and  more  may  be  found.  Zones  of  dolomite  and 
dolomitic  limestone  are  very  common  in  the  Ste.  Genevieve,  St.  Louis, 
and  Salem  limestones.  These  zones  are  very  persistent  and  can  be 
traced  in  wells  throughout  the  Illinois  basin.  The  porous  zones  may 
carry  salt  water  and  may  also  have  small  oil  showings.  The  Leach 
Brothers'  Albert  Lee  No.  i,  Sec.  11,  T.  i  S.,  R.  10  E.,  Edwards 
County,  had  a  showing  of  oil  in  one  of  these  porous  dolomitic  zones 
in  the  Salem  limestone.  In  Lawrence  County  high  on  structure  two 
or  three  wells  on  the  Bowers  and  Ross  lease.  Sec.  29,  T.  4  N.,  R.  12  W., 
obtained  production  from  a  dolomite  zone  at  the  top  of  the  St.  Louis 
limestone,  and  200  feet  below  the  top  of  the  Ste.  Genevieve. 

Another  area  of  St.  Louis  production  of  considerable  interest  is 
the  Nollem  Oil  and  Gas  Company's  Kelley  No.  i.  Sec.  25,  T.  4  S., 
R.  2  E.,  Jefferson  County,  which  obtained  production  at  a  depth  of 
3,002  feet,  100  feet  below  the  top  of  the  St.  Louis  limestone.  Produc- 
tion is  in  a  porous  zone  in  the  fossiliferous  limestone  which  is  of  very 
local  occurrence.  Wells  drilled  north  and  south  of  the  discovery  well 
were  dry. 

SOUTHEASTERN  ILLINOIS  FIELD 

To  date  production  below  the  McClosky  sand  in  the  southeastern 
Illinois  oil  field  is  practically  limited  to  the  northern  part  in  Clark 
County.  The  Westfield  limestone,  which  is  the  main  producing  forma- 
tion of  the  Westfield  pool,  underlies  the  Pennsylvanian  at  a  depth  of 
400  feet  and  includes  the  St.  Louis  and  Salem  limestones  of  the 
Lower  Mississippian  series.  A  well  drilled  in  Sec.  17,  T.  11  N.,  R.  14 


8i6    ALFRED  E.  BELL  AND  GEORGE  V.  COHEE 

W.,  logged  75  feet  of  St.  Louis  limestone  overlying  the  Salem  lime- 
stone. It  is  estimated  that  approximately  50  feet  of  St.  Louis  is 
present  on  top  of  the  dome.  Most  of  the  production  is  obtained  from 
the  upper  50  feet  of  the  limestone  whereas  on  the  sides  of  the  dome  it 
may  be  as  much  as  100  feet  below  the  top.  Very  little  production  has 
been  obtained  at  greater  depths  in  the  limestone.  There  are  from  one 
to  three  pays  in  dolomitized,  slightly  oolitic,  pure  or  impure  limestone 
zones.  The  range  in  porosity  is  very  wide  owing  to  the  varying  degree 
of  dolomitization  and  oolitic  content.  Very  porous  streaks  are  usually 
less  than  10  feet  thick  and  vary  from  10  to  100  feet  apart. 

The  "Trenton"  (Kimmswick-Plattin)  limestone  which  is  geologi- 
cally the  oldest  producing  formation  in  Illinois,  is  productive  in  11 
wells  near  the  top  of  the  Westfield  dome.  The  limestone  is  reached  at 
a  depth  of  about  2,270  feet  and  the  pay  was  found  in  the  upper  150 
feet  of  the  limestone.  The  oil  occurs  in  pure  crystalline  limestone 
which  is  more  porous  in  the  lower  part.  The  wells  had  a  flush  produc- 
tion of  approximately  100  barrels  after  shooting,  but  within  two  or 
three  months  dropped  to  10  or  12  barrels  a  day  on  pump. 

The  St.  Peter  sandstone  was  tested  on  structure  in  the  Tidewater 
Associated  Oil  Company's  Spellbring  No.  34,  Sec.  8,  T.  1 1  N.,  R.  14  W. 
The  top  of  the  sand  was  reached  at  2,984  feet;  the  well  was  drilled  to 
3,009  feet. 

In  the  Westfield  pool  the  structure  is  a  broad,  well  defined  dome 
with  about  180  feet  of  closure  on  the  eroded  top  of  the  Lower  Missis- 
sippian  limestone  and  about  300  feet  of  closure  on  the  top  of  the 
"Trenton."  The  top  of  the  "Trenton"  structure  appears  to  be  about 
\  mile  west  of  the  top  of  the  structure  on  the  Mississippian  limestone. 

In  the  Martinsville  pool  the  St.  Louis  limestone  which  immediately 
underlies  the  Pennsylvanian  is  productive.  Locally  the  pay  stratum 
has  been  called  the  Martinsville  "sand."  It  is  in  the  porous,  somewhat 
altered  zone  in  the  limestone  usually  from  5  to  10  feet  below  the  top 
and  averages  20  feet  in  thickness. 

The  Carper  sand,  consisting  of  one  to  four  sandstone  lenses,  each 
ID  to  30  feet  thick,  is  in  the  lower  Osage  group.  The  sandstones  are 
fine-grained  and  occur  in  lenticular  beds  of  variable  thickness  and 
considerable  areal  extent.  Each  bed  is  separated  by  10  to  15  feet  of 
shale.  The  top  sand  is  usually  barren  of  oil  and  the  second  sand  is  the 
principal  producer.  Much  gas  was  produced  with  the  oil  near  the  crest 
of  the  structure. 

Mylius  (i)'  considered  the  Carper  sand  upper  Kinderhook  in  age 
and  Moulton  (2)  placed  the  sand  "in  the  black  shale  underlying  the 

^  For  references,  see  end  of  article. 


RECENT  DEVELOPMENT  IN  ILLINOIS  817 

Mississippian  limestone."  Later  studies  in  the  Martinsville  field  by 
L.  E.  Workman  and  J.  N.  Payne*  show  that  the  Carper  sand  is  basal 
Osage.  All  of  the  sandstones  that  have  been  called  the  Carper  sand 
occur  above  the  Rockford  limestone  which  is  near  the  top  of  the 
Kinderhook  in  this  part  of  Clark  County.  A  sandstone  may  be  present 
in  certain  areas  beneath  the  Rockford  limestone,  but  it  is  of  local 
occurrence  and  very  thin. 

The  Devonian-Silurian  limestone  which  has  been  called  "Niaga- 
ran"  and  "Corniferous"  is  productive  in  the  Martinsville  pool.  Pro- 
duction is  from  the  weathered  zone  in  the  upper  part  of  the  limestone 
and  the  best  production  is  found  10  to  30  feet  from  the  top.  Much 
water  has  been  produced  with  the  oil  from  this  zone. 

The  "Trenton"  has  been  tested  in  two  wells,  both  on  the  west 
slope  of  the  structure,  one  of  which  was  dry.  The  other  produced  a 
small  amount  of  oil  from  a  coarsely  crystalline  limestone,  somewhat 
sandy  toward  the  base.  The  producing  well  on  the  McFarland  farm, 
Sec.  19,  T.  10  N.,  R.  13  W.,  was  drilled  125  feet  into  the  "Trenton" 
limestone,  reached  at  a  depth  of  2,708  feet.  The  Lowe  dry  hole  was 
drilled  in  Sec.  25,  T.  10  N.,  R.  14  W.  The  top  of  the  "Trenton"  was 
reached  in  this  well  at  a  depth  of  2,709  feet. 

The  structure  in  the  area  is  an  elongate  dome  on  the  side  of  and 
somewhat  parallel  with  the  major  fold  of  the  LaSalle  anticline.  There 
is  a  closure  of  20  feet  on  top  of  the  eroded  St.  Louis  limestone  and  less 
than  100  feet  on  the  top  of  the  Devonian.  The  Trenton  Rock  Oil  Com- 
pany's Carper  No.  13,  Sec.  30,  T.  10  N.,  R.  13  W.,  total  depth  3,411 
feet,  was  drilled  to  the  St.  Peter  sandstone,  the  top  of  which  was 
reached  at  a  depth  of  3,400  feet. 

In  northern  Crawford  County  the  Salvage  Oil  and  Fuel  Company's 
W.  S.  McGrillis  No.  6,  Sec.  25,  T.  8  N.,  R.  13  W.,  had  a  good  showing 
of  oil  and  gas  in  the  Devonian  limestone  topped  at  a  depth  of  2,775 
feet,  total  depth  2,785  feet.  This  well  has  created  considerable  interest 
in  the  possibilities  of  deeper  production  in  Crawford  County  where 
the  principal  producing  horizon  is  the  Robinson  sand  of  Pennsyl- 
vanian  age.  Small  production  has  been  obtained  locally  near  Oblong, 
Illinois,  in  a  deeper  sand  which  has  been  correlated  as  the  McClosky 
sand. 

The  Hastings  et  al.  Athey  No.  i,  Sec.  18,  T.  8  N.,  R.  12  W.,  a  few 
miles  northeast  of  the  McGrillis  well,  tested  the  Devonian  and  had  a 
fair  showing  of  oil.  Southeast  of  Stoy,  Illinois,  and  within  the  produc- 
ing area  of  the  Robinson  sand,  the  Zanhizer  et  al.  Jones  well  tested 
the  "Trenton"  limestone  in  Sec.  12,  T.  6  N.,  R.  13  W.  The  top  of  the 

*  Personal  communication. 


8i8  ALFRED  H.  BELL  AND  GEORGE  V.  COHEE 

Devonian  was  reached  at  the  depth  of  2,896  feet,  the  "Trenton"  at 
4,243  feet,  and  the  total  depth  of  the  well  was  4,620  feet.  Showings  of 
oil  were  reported  in  the  Devonian  at  2,900  feet  and  3,130  feet.  It  is 
expected  that  several  tests  will  be  drilled  to  the  Devonian  in  the  near 
future.  To  date  these  three  wells  are  all  that  have  been  drilled  to  the 
Devonian  in  Crawford  County. 

Lawrence  County  has  likewise  had  very  little  deep  drilling.  A 
well  drilled  in  the  Middaugh  farm  in  Sec.  32,  T.  4  N.,  R.  12  W.,  tested 
the  St.  Peter  sandstone.  This  well  was  drilled  on  the  axis  of  the  anti- 
cline, i|  miles  southeast  of  the  crest  as  mapped  on  the  Kirkwood  sand. 
There  was  a  showing  of  oil  in  the  Devonian  limestone  at  2,965  feet. 
The  top  of  the  "Trenton"  was  4,370  feet,  the  St.  Peter  sandstone 
5,180  feet  and  the  total  depth  5,190  feet.  No  showings  were  recorded 
below  the  Devonian.  Another  well  was  drilled  to  the  Devonian  within 
the  area  of  production  but  toward  the  south  edge  in  the  Lawrence 
County  field.  The  L.  Jenner,  Central  Refining  Co.  No.  21  in  Sec.  35, 
T.  3  N.,  R.  12  W.,  was  drilled  to  a  depth  of  3,515  feet.  Two  showings 
of  oil  were  recorded  in  the  Devonian  limestone  which  was  topped  at 
3,145  feet — one  showing  at  3,303  feet  and  the  other  at  3,348  feet. 
Another  well  was  drilled  to  the  Devonian  at  the  eastern  edge  of  the 
county  and  a  number  of  miles  from  production;  no  showings  were 
recorded. 

Wabash  County  has  had  no  wells  that  were  drilled  to  the  Devonian 
or  deeper. 

JACKSONVILLE  GAS  FIELD 

Much  of  the  gas  and  a  small  amount  of  oil  has  been  produced  from 
the  Mississippian  limestone  in  the  Jacksonville  gas  field  2  miles  east 
of  Jacksonville,  Illinois.  Some  gas  has  been  produced  from  the  Penn- 
sylvanian  sandstone,  as  well  as  from  the  underlying  Mississippian 
limestone,  correlated  as  the  Salem  (9).  The  principal  production  is 
from  a  porous  dolomitic  zone  near  the  top  of  the  limestone.  The  field, 
abandoned  in  1937,  had  more  than  50  gas  wells.  The  gas  was  used  for 
heat  and  light  in  local  residences  and  was  also  piped  to  the  city  of 
Jacksonville.  A  few  wells  are  still  being  used  by  the  landowners. 

The  structure  of  the  beds  beneath  the  Pennsylvanian  uncon- 
formity is  not  known  in  detail  because  the  wells  in  the  area  were  drilled 
only  a  short  distance  into  the  limestone.  However,  it  is  possible  that 
the  form  of  the  erosional  surface  may  have  been  controlled  by  the 
folding  of  the  underlying  Mississippian  strata.  Contours  on  the  ero- 
sional surface  at  the  top  of  the  limestone  show  a  high  in  Sees.  2  and 
3,  T.  15  N.,  R.  9  W.,  where  gas  was  produced.  Oil  was  found  lower 


RECENT  DEVELOPMENT  IN  ILLINOIS  819 

structurally  on  saddles  between  structures.  A  well  was  drilled  to  the 
"Trenton"  in  Sec.  8,  T.  15  N.,  R.  9  W.,  in  one  of  the  areas  of  gas  and 
oil  production.  The  well  was  drilled  148  feet  in  the  "Trenton"  and  no 
showings  were  recorded  in  the  Devonian  or  "Trenton"  limestone.  The 
top  of  the  Warsaw  shale  and  limestone  is  reached  at  a  depth  of  ap- 
proximately 400  feet  in  this  area;  this  is  the  shallowest  horizon  below 
the  unconformity  suitable  for  a  key  horizon  for  structure  testing.  The 
Salem  limestone  is  only  100  to  150  feet  thick  in  the  field. 

COLMAR-PLYMOUTH  FIELD 

In  1914  oil  was  discovered  on  the  Hoing  farm  in  Sec.  16,  T.  4  N., 
R.  4  W.,  McDonough  County.  The  field  was  rapidly  developed  and 
resulted  in  two  separate  producing  areas;  one  largely  in  Sees.  15  and 
16,  T.  4  N.,  R.  4  W.,  which  has  frequently  been  called  the  east  pool 
and  the  other  to  the  southwest  in  Sees.  19  and  30,  T.  4  N.,  R.  4  W., 
and  extending  into  the  eastern  edge  of  Hancock  County.  This  pool 
has  been  referred  to  as  the  south  pool.  Four  hundred  seventy-seven 
wells  have  been  drilled  in  the  field  and  2,416,000  barrels  of  oil  were 
produced  to  the  end  of  1938. 

The  producing  formation,  the  Hoing  sand,  is  a  lenticular  sand- 
stone averaging  21  feet  in  thickness,  occurring  in  lenses  at  the  base 
of  the  Cedar  Valley  dolomitic  limestone  and  in  depressions  on  top 
of  the  Maquoketa  shale.  In  this  area  the  Silurian  is  absent  and  the 
Devonian  Hoing  sand  rests  on  the  Ordovician  Maquoketa  shale.  The 
character  of  deposition  of  the  sandstone  and  subsequent  erosion  ac- 
count for  its  irregular  occurrence  in  the  field. 

Blatchley  and  Savage  (4)  considered  the  Hoing  sand  of  Devonian 
age  "Hamilton  (?)"  and  later  Morse  and  Kay  (5)  and  Hinds  (6)  de- 
fined the  "sand"  as  Silurian.  After  studying  numerous  sets  of  well 
cuttings  from  the  field  and  adjacent  area  Workman  (7)  correlated 
the  sand  as  Devonian  in  age  because  the  sand  grains  of  which  the 
Hoing  sand  is  composed  are  not  present  in  the  Maquoketa  shale  or  in 
the  Silurian  which  is  present  near  by.  The  sand  grains  resembling  those 
of  the  Hoing  sand  are  found  widespread  in  basal  Devonian  strata  in 
Illinois. 

The  structure  of  the  field  as  shown  by  the  contours  on  the  Col- 
chester No.  2  coal  consists  of  a  dome  with  an  east-west  axis  about 
half  way  between  Comar  and  Plymouth  and  a  terrace  on  the  northeast 
edge  of  the  dome  i^  miles  east  of  Colmar.  The  dome  and  terrace 
have  a  combined  closure  of  60  or  more  feet.  Production  occurs  on  top 
and  well  down  the  side  of  the  dome. 

The  "Trenton"  limestone  has  been  tested  in  a  number  of  wells 


820    ALFRED  H.  BELL  AND  GEORGE  V.  COHEE 

drilled  on  the  dome,  but  to  date  no  well  has  tested  the  "Trenton" 
on  the  terrace  where  the  east  pool  is  located. 

DECATUR  FIELD 

In  1922  and  1924  several  oil  tests  were  drilled  to  the  Devonian 
limestone  in  the  vicinity  of  Decatur,  Illinois.  The  top  of  the  limestone 
was  reached  at  a  depth  of  1,950  feet  to  2,000  feet.  A  number  of  the 
wells  had  showings  of  oil  in  the  Devonian  but  not  sufficient  for  com- 
mercial production.  In  1937,  two  of  the  old  wells  in  Sec.  33,  T.  17  N., 
R.  2  E.,  and  Sec.  5,  T.  16  N.,  R.  2  E.,  a  short  distance  northwest  of 
Decatur,  were  cleaned  out,  acidized,  and  made  small  producers.  The 
Devonian  limestone  is  only  10  to  20  feet  thick  in  this  area.  Contours 
on  coal  No.  5  show  an  anticlinal  nose  northwest  of  town  with  a 
northwest  trend.  Last  year  a  dry  hole  was  drilled  in  Sec.  30,  T.  17  N., 
R.  2  E.,  to  the  St.  Peter  sandstone  and  was  found  to  be  higher  on  the 
structure  than  the  above  mentioned  producing  wells.  Here  the 
Devonian  was  entirely  removed  and  no  showings  were  recorded  in  the 
Silurian  or  "Trenton"  limestones. 

PIKE  COUNTY  GAS  FIELD 

Gas  was  discovered  on  the  Pittsfield-Hadley  anticline  in  1886,  but 
the  gas  field  on  the  anticline  west  of  Pittsfield,  Illinois,  was  not  de- 
veloped until  after  1905.  Gas  was  found  in  the  Niagaran  dolomite  of 
Silurian  age.  The  producing  formation  is  overlain  by  shale  of  Upper 
Devonian  and  Lower  Mississippian  age  (10,  11).  On  the  highest  part 
of  the  structure  the  Upper  Devonian  shale  lies  directly  below  the 
Pleistocene.  The  average  depth  to  the  top  of  the  producing  zone  is 
265  feet.  The  gas  wells  were  scattered  over  an  area  of  almost  9,000 
acres.  The  gas  was  used  locally  by  the  landowners  to  heat  and  light 
their  residences.  The  structure  is  an  elongate  anticline  with  smaU 
domes  along  the  main  axis,  each  dome  having  40  to  60  feet  of  closure. 
The  main  axis  of  the  fold  has  northwest  trend  and  extends  from  Lewis 
County,  Missouri,  through  Adams,  Pike,  and  into  Greene  counties, 
Illinois  (13).  A  number  of  wells  on  structure  have  been  drilled  to  the 
St.  Peter  sandstone  which  is  reached  at  the  depth  of  750  to  800  feet. 

COLLINSVILLE  FIELD 

Near  CoUinsville,  Illinois,  four  wells  were  drilled  in  Sec.  8,  T.  3  N., 
R.  8  W.,  Madison  County,  and  found  production  in  Devonian-Silurian 
limestone.  The  "sand"  according  to  the  driller's  logs  was  20  to  30 
feet  thick.  The  greater  part  of  the  sand  is  in  the  Silurian  as  the 
Devonian  is  represented  by  approximately  5  feet  of  calcareous  sand- 
stone. The  wells  were  small  and  were  soon  abandoned. 


RECENT  DEVELOPMENT  IN  ILLINOIS  821 

Although  the  available  data  are  insufficient  to  determine  the 
nature  of  the  reservoir,  there  is  a  suggestion  that  a  structure  of  small 
areal  extent  gave  rise  to  the  accumulation.  The  "Trenton"  has  not 
been  tested  in  the  vicinity  of  the  production. 

DUPO  AND  WATERLOO  OIL  FIELDS 

The  Dupo  oil  field  discovered  in  1928  is  located  on  the  Waterloo 
anticline  which  has  a  north  trend  and  extends  from  St.  Louis,  Mis- 
souri, to  Waterloo,  Illinois  (12).  The  Waterloo  field  which  was  dis- 
covered 8  years  prior  to  Dupo  was  of  less  importance.  It  had  only  23 
producing  wells  and  all  were  abandoned  by  1930.  The  producing  hori- 
zon in  both  fields  is  a  porous  zone  in  the  light  brown,  crystalline 
Kimmswick  ("Trenton")  limestone  occurring  at  the  top  of  the  lime- 
stone at  a  depth  of  500  feet.  The  wells  are  drilled  40  to  50  feet  in  the 
limestone.  To  date  242  wells  were  drilled  in  the  field  and  approxi- 
mately 950,000  barrels  of  oil  have  been  produced.  Town  lot  drilling 
at  the  north  end  of  the  field  hastened  the  rapid  decline  of  the  wells  in 
that  area  and  all  but  25  of  the  wells  have  been  abandoned.  A  few  wells 
have  recently  been  drilled  at  the  eastern  edge  of  the  field  and  found 
production  in  crevices  in  the  limestone  according  to  information  from 
drillers.  This  development  has  caused  a  revived  interest  in  the  field. 

Both  the  Dupo  and  Waterloo  fields  on  the  Waterloo  anticline  are 
located  on  separate  domes  with  100  feet  or  more  of  closure.  The  anti- 
cline is  a  long,  narrow  structure  with  a  steep  west  dip  and  a  gentle 
east  dip.  The  fold  dies  out  to  the  north  under  St.  Louis  and  to  the 
south  a  short  distance  south  of  Waterloo.  Only  200  feet  of  Mississip- 
pian  strata  are  encountered  in  wells  on  the  anticline;  the  Devonian  is 
absent  and  the  Silurian  is  represented  by  50  or  70  feet  of  dolomitic 
limestone.  I.  G.  Lockwood's  Dyroff  No.  i,  Sec.  26,  T.  i  N.,  R.  10  W., 
located  on  the  flank  of  the  structure,  tested  the  St.  Peter  sandstone. 

HERSCHER  AREA 

An  area  of  passing  interest  which  produced  some  oil  and  gas  from 
the  "Trenton"  is  in  Sec.  32,  T.  30  N.,  R.  10  E.,  Kankakee  County 
(14).  Nine  wells  drilled  in  the  north  half  of  the  section  produced  oil 
and  gas  for  a  short  time  before  being  abandoned.  The  largest  well 
produced  only  |  barrel  a  day.  All  wells  produced  some  gas,  the  largest 
being  32,000  cubic  feet  per  day.  The  "Trenton"  was  reached  at  a 
depth  of  140  feet  and  it  is  not  known  at  what  depth  below  the  top  of 
the  limestone  the  oil  was  reached.  Several  wells  were  drilled  in  the 
area,  but  few  logs  are  available  and  the  available  data  are  not  suf- 
ficient to  explain  the  structural  conditions  which  gave  rise  to  this 


822    ALFRED  E.  BELL  AND  GEORGE  V.  COHEE 

local  occurrence  of  oil  off  the  flank  of  the  Kankakee  arch.  There  are 
several  areas  in  northwestern  Indiana  along  the  Kankakee  arch  in 
which  oil  was  produced  from  the  "Trenton"  (15). 

CONCLUSION 

In  view  of  the  numerous  areas  of  Devonian  and  "Trenton"  pro- 
duction in  the  state  and  the  recent  finding  of  Devonian  production  in 
the  Sandoval  field,  the  possibilities  for  new  production  below  the 
McClosky  "sand"  deserve  serious  consideration.  Up  to  the  beginning 
of  the  recent  development  production  from  these  strata  amounted 
only  to  about  one  per  cent  of  the  state's  total  production.  It  is  possible 
that  they  will  be  important  producing  zones  in  such  fields  as  Louden 
(Beecher  City),  Salem  (Lake  Central] a),  Centralia,  Patoka,  and  cer- 
tain central-basin  fields.  In  the  central-basin  fields  the  depth  of  the 
Devonian  is  estimated  to  be  4,500  to  5,100  feet  and  the  "Trenton" 
5,900  to  6,500  feet. 

ACKNOWLEDGMENTS 

For  certain  areas  discussed  in  the  manuscript  the  writers  wish  to 
acknowledge  use  of  information  from  the  publications  listed  as  ref- 
erences. 

REFERENCES 

1.  L.  A.  Mylius,  "Oil  and  Gas  Development  and  Possibilities  in  East  Central  Illinois," 

Illinois  State  Geol.  Survey  Bull.  §4  (1927). 

2.  G.  F.  MouLTON,  "Areas  for  Further  Prospecting  Near  the  Martinsville  Pool,  Clark 

County,  Illinois,"  Illinois  State  Geol.  Survey  Illinois  Petroleum  4  (1926). 

3.  ,  "Structure  and  Oil  Prospects  of  Eastern  Clark  County,  Illinois,"  ibid.  14 

(1928). 

4.  R.  S.  Blatchley,  "Plymouth  Oil  Field,"  Illinois  State  Geol.  Survey  Bull.  23  (1917), 

pp.  51-53. 

5.  W.  C.  Morse  and  F.  H.  Kay,  "The  Area  South  of  the  Colmar  Oil  Field;  the  Cohnar 

Oil  Field,  a  Restudy,"  ibid,  ji  (1915). 

6.  Henry  Hinds,  "Colchester-Macomb,"  U.  S.  Geol.  Survey  Geol.  Atlas  Folio  208 

(1919). 

7.  L.  E.  Workman,  "The  Stratigraphic  Position  of  the  Hoing  Sand,"  Illinois  State 

Acad.  Sci.,  Vol.  26  (1934),  p.  107. 

8.  D.  M.  CoLLiNGWOOD,  "Oil  and  Gas  Development  in  the  Vicinity  of  Jacksonville," 

Illinois  State  Geol.  Survey  Bull.  44B  (1923). 

9.  Alfred  H.  Bell,  "Recent  Development  in  the  Vicinity  of  Jacksonville,"  Illinois 

State  Geol.  Survey  Illinois  Petroleum  11  (1927). 

10.  H.  N.  Coryell,  "Parts  of  Pike  and  Adams  Counties,"  Illinois  State  Geol.  Survey 
Bull.  40  (1919),  pp.  70-95. 

11.  Alfred  H.  Bell,  "Oil  Prospects  in  Central  Pike  County,"  Illinois  State  Geol. 
Survey  Illinois  Petroleum  j  (1926),  pp.  7-10. 

12.  Alfred  H.  Bell,  "The  Dupe  Oil  Field,"  ibid.  17  (1929). 

13.  Frank  Krey,  "Structural  Reconnaissance  of  the  Mississippi  Valley  Area  from 
Old  Monroe,  Missouri,  to  Nauvoo,  Illinois,"  Illinois  State  Geol.  Survey  Bull.  45 
(1924),  PI.  I. 

14.  L.  F.  Athey,  "Geology  and  Mineral  Resources  of  the  Herscher  Quadrangle," 
ibid.  §s  (1928),  pp.  109-110. 

15.  W.  N.  Logan,  HaiMook  of  Indiana  Geology,  Pt.  5,  Chap.  10  (1922).