92 CARBONIFEROUS LIMESTONES OF IOWA. 
SECTION OF SUBCARBONIFEROUS LIMESTONES OF IOWA. 
ree Bituminous shales. 
‘oal, 
| Bed of coal, six to eighteen inches thick. 
COAL MEASURES. 3 
a Gray argillaceous shales. 
m 
390 gps 
oss . \ § White, brittle, close textured limestone; usually irregularly bedded and concre- 
Rn : 
380 i S23 tionary. 
. BES , 
370 hee own and white gritstones, nannie d a remains of Lepidodendron, 
360 e’ | Gritstones. calamites, and other carboniferous plan 
350 do ( Lower, compact, white limestone, usually concretionary; sometimes magne- 
é eI zt sian, with earthy | matter | and marlite in the interstices ; containing two or 
340 ra vis . 8 ore species of L 
| ue hess b Louis, al species 
E =." of Productus, Sparifer (Wesubetus?) , and reticulated ‘aaa of. the genera 
ea 
330 Fe ss Retepora and Fine. 
a re] 
3 5 ce’ | Gritstones Sandstone, sometimes with small Nahe meg ter cd. 
20 re pitti Vingnesian Argillaceous, cherty, and marly partin Locally hydraulic limestone. 
ar magnesian building-s oder ocally wi vedio ar ramifications 
~ b’ Riureakies Cellul n buildi t 7 1} ith 1 ifie ti 
310 =| and green particles disseminated. Containing reticulated corals and 
a * apriiratam Royssii. 
300 a S 
= a’ 23 Impure limestones, taining cavities lined witt p d geod 
290 3a 
a 
i S 
280 = 
S 
270.) a, b 
a g ( Lge foi limestones with marly partings, containing Ar- 
260 3 a also brown calcareous beds, with ve lined with : 
= m are onl impure limestones charged with mi te Spirifers ; 
vo 
250 > Pf 3 FS together with ae gray Soe neeones, con Selntog Terebratula 
lol ae Royssti, Orthis aculum, 
| ao 
240 5 
tal < 
La | 
2380 2 —— wey crystalline limestones, containing Spirifer striatus, 
| 3 3 S. cuspidatus, S. rotundutus, Productus punctatus, P. 
220 5 ele 3 semireticulatus, &e. 
< 
Keokuck 
210 5 « |Che =n Cherty limestones of Keokuck. 
9 3 Limestones, 
00 3 
=) & 
s 
190 Ss 8 z 
BE | 8 | Is 
180 | 2 é 3 | | 
al = : 
170 | & a Be Pa clase aide el 
=) 2 e186 g 
. ; 3 chert, as near Hannibal. 
160 | g | & “fe 
=) r=) 
150 Fe z | 5 
a g 3 
BOR Bite 
= | & § White sages By and semiodlitic limestones, con- 
fe ing 
130 3 iy 4 2 taini cora and Spirifer cuspidatus. 
z a niga and Meany rere encrinital limestones, 
120, = 2 Ss containing several soecies of Pentremites, Pluty- : 
i By a = _ crinus, Actinocrinus, and Poteriocrinus.” 
10 a - é 4 
a E és : 
100 - b| as Jerk! Bapsen Hy crinoidal limestones with crys- 
: BE ) Band of cellular, buff, magnesian limestone. 4 
ba 8 ; Oilitic limestone, containing Gyroceras Burling- 2 
= 
80 5 Dark argillaceous limestones (locally hy- 
70 Buff, fine-grained siliceous rock, contai 
C0! ning casts 
60 & ; of hana Posidonomya, Allorisma, Spirifer, 
z 
Se 
50 $3 
Zs 
40 ~ ee 
= 
30 bt Ash-coloured, earthy marlites, 
20 ia 
< § Slope, rocks hidden by talus and 
10 | ? ds of the Mississippi River. 
