1918] Moody-Taliaferro : Anticlines Near Sunshine, Wyoming 453 



and without crossed nicols the spots are a dark gray and stand out 

 sharply from the mass of the rock, which is pale brown in color, and 

 which is made up of cryptocrystalline silica. The spots are usually 

 somewhat elliptical and average 0.66 by 0.45 mm. With crossed 

 nicols the spots are indistinguishable from the mass of the rock, the 

 whole being largely isotropic. The spots are somewhat more cloudy 

 than the remainder of the rock, but otherwise they are quite similar 

 to it. The slight banding of the chert passes through the spots with- 

 out any change in character. These spots seem to be made up of opal 

 or of amorphous silica and it is possible that they represent centers 

 of weathering. Two small radiolarian tests were seen in this slide. 

 They were 0.12 mm. in diameter. 



Frontier Formation. — The Frontier formation consists of about 

 600 feet of sandstone and shale, the ratio of sandstone to shale being 

 about seven to five. The degree of induration of the sandstones is 

 variable, individual beds changing rather rapidly from hard and well 

 cemented to soft and crumbling layers. The cement is generally cal- 

 careous. The thickness of individual beds is not constant. The lowest 

 sandstone, for example, is 40 feet thick at the northern end of the 

 Sunshine anticline and more than 60 feet thick on the east limb of 

 the Gooseberry Creek fold. In general the sandstones are white to 

 buff in color, cross bedded, fine to coarse grained, and with only a 

 small percentage of ferro-magnesian constituents. Carbonized wood 

 fragments are present in some of the layers of the upper sandstone 

 member. This formation outcrops along the flanks of the Sunshine 

 and Gooseberry Creek anticlines and forms the crest of the small 

 minor fold lying between these anticlines. In general the sandstone 

 members of the Frontier formation form low, rather well wooded 

 ridges, separated by shallow depressions which are occupied by the 

 shales. 



The following section is given by Hintze 



Section of Upper Part op Benton Formation, on Wood Eiver 



Cody shale. feet 



Light brown sandstone, upper layers conglomeratic 62 



Sandy shale and dark adobe shale 167 



Light gray massive sandstone 64 



Light brown and gray, thick bedded sandstone 108 



Hard, white massive sandstone 54 



Light brown sandy shale, thin bedded 83 



Massive hard gray sandstone 45 



Total 583 



4 Hintze, F. F., Jr., The Little Buffalo Basin oil and gas field, loc. ext., p. 75, 

 1915. 



