FORMING THE BAD LANDS OF JUDITH RIVER. 135 
Vertical Section, Exhibiting a Portion of the Strata of the Great Lignite Basin, near Fort 
Clarke, on Missourt. 
| 
Ferruginous sandy marl, passing downwards into varie- 
Fort Union, Yellow Stone, Red 
Spring, ten miles above Fort Clarke. 
A! 380 fect. gated argillaceous grits; coutains Paludina Leat, 
P. retusa, P. Leidyi, P. trochiformis. 
B| 2 inchs’.| Seam of impure reddish lignite. Red Spring to Fort Union. 
Best developed and most fossiliferous 
1! 10 to12 Yellowish gray, friable grit, with numerous argilla- at Red Spring, ten miles above Fort 
C ee ai ceous concretions in horizontal layers, containing Clarke. It occurs also along the Mis- 
cele beautiful impressions of leaves of the genera, Pla- souri to Fort Union, where it contains 
tanus, Acer, Ulmus, and Ferns. fine impressions of Ferns as well as Di- 
ae cotyledonous leaves. 
D | 3 inchs’.| Seam of lignite, very much mixed with clayand sand. Red Spring and up the Missouri. 
a Yellowish gray grit, very friable, and containing lay- 
FE) 10 feet. ers of argillo-caleareous concretions, charged with Red Spring, &e. 
; leaves of the same species of plants, as in bed C. 
HF! 3 inchs’.| Scam of earthy lignite. Red Spring, &e. ; 
: Yellow and drab clay and friable sandstone, contain- 
G15 feet. ing argillaceous concretions, with impressions of Red Spring to Fort Union. 
leaves like those in beds C. and Ht. 
H) 4 inchs’.| Dark reddish, earthy lignite. Red Spring, &c. 
Yellow arenaceous erit, very friable, with some small e 
I | 20 feet. Paludinas, Corbulas, de. Jeel ype 
Alternations of lignite and clay. This bed is vari- Fort Clarke, Red Spring, and other 
Till 1S Aaah. able in thickness as well as in the proportions localities along the Missouri. 
of the materials at different localities; contains 
large quantities of fresh water shells. 
Heavy bedded gray and ferruginous friable sand- 
stone, with great numbers of fossils, forming seams Very largely developed at Fort 
of shell marl; Melania Nebrascensis, Paludina Clarke, Red Spring; is also seen 
K_| 40 feet. multilineata, P. peculiaris, Bulimus Umnea- where the ‘Tertiary beds are exposed 
Jormis, Corbula mactriformis, with numerous along Missouri and Yellow Stone. 
impressions of Dicotyledonous leaves in argillo- 
calcareous concretions. 
L | 2 feet. Seam of impure lignite, probably local. ee Spriug; not seen at many lo- 
ae Gray argillaceous friable grit, usually passing down- Fort Clarke, Red Spring, and aiong 
M gets wards into a dark brown carbonaceous clay. Missouri. 
Tig P ; Fort Clarke to Fort Berthold, to 
N | 2 feet. Lignite, purest in the section. oct Union 
ae ~ | Very dark carbonaceous clay passing down into very 
bluish gray arenaceous clay, contains at Fort | . Fort Clarke, Red Spring, Fort Ber- 
O| 6 feet. Berthold a species of Paludina, also Planorbis thold and Fort Union. It is also seen 
fragilis, and a few impressions of leaves, petri- above Fort Union along the Missouri. 
fied wood, &e. 
: p ; About 70 miles below Fort Clarke 
9 F 5 ‘ 4 3 bed is : 5 : ? 
P| 2 feet. Rather pure lignite. This bed is local. dear the pointiwherethe!Tertiary beds 
oa u first appear in ascending the Mo. 
Gray compact or somewhat friable concretionary : = 
Q} 40 to60 sandstone; contains Cyrena Moreauensis, C. in- Near Long Lake on the Missouri. 
feet. termedia, Thespesius occidentalis, Compsemys On Moreau River and Cherry Creek. 
victus, He. 
