EPICONTINENTAL SEA OF JURASSIC AGE 257 
or the underlying beds. For the Jura in many localities, so far 
as physical characters are concerned, grades almost impercep- 
tively into the Red Beds below and the Como above. 
Judith Mountains.*—Weed and Pirsson give the following 
section as representing the Jura in the Judith Mountains. 
The base is separated from the Carboniferous by a sheet of 
porphyry. 
Feet, 
Limestone, dark gray, laminated, and shaly - - - - 10 
2. Limestone, blue to gray in color, hard in texture, and carrying 
Ostreze in 3 to 5-foot beds, separated by thinner platy beds - 12 
3. Noexposure - . - - - = - - - - 25 
4. Shaly, argillaceous, impure limestone, dove colored, weathering buff 
on joint faces and of typical Jurassic aspect - - - 5 
5. Shaly beds, seldom exposed, carrying oolitic limestone. Green or 
sandy limestone of drab color - - - - - - 15 
6. Rough weathering limestone, fine grained, cross-bedded and fissile, 
carrying fossils - - : 2 = > . = . 5 
7. Sandy limestone like that above, but irregularly bedded and resem- 
bling sandstone; granular and saccharoidal in texture, carries shell 
fragments - - - 2 - - - - - - 4 
8. Irregularly platy, earthy-brown, gray limestone carrying shell 
remains of Gryphea and Ostrea, weathering dark brown, rarely 
granular - - - - - - - - - - 6 
g. Marly shales and limestone, dove colored, carrying fossils noted in 
following pages, seldom exposed, Gryfhea most abundant here - 30 
10. No exposure, but débris of sandstone’ - - - 2 60 
11. Ellis sandstone, variable, buff, platy sand rock; pink blotched at base 
with occasional shells; cross-bedded purple-brown outcrop. It is 
at the top a limestone full of black and white quartz sand grains 
and forms a dark brown ridge - - - - - - - 12 
This section gives the total thickness of the Jura for this 
region at 184 feet, which is nearly double that of the Little 
Rocky and Castle Mountain areas. 
The fossils collected from the horizon mentioned above are : 
Ostrea strigilecula White; Gryphea calceola var. nebrascensis M. & 
H.; Wodiola subimbricata M.; Cucullaea haguet M.; Pleuromya sub- 
compressa M. 
WEED and Pirsson, Eighteenth Ann. Rept., U. S. Geol. Surv., III, p. 445. 
