1918] Moody-Taliaferro: Anticlines Near Sunshine, Wyoming 457 



both ends of the fold. The southern end of the fold is covered by the 

 Wasatch formation which unconformably overlies the older formations 

 and on the north much of tbe anticline is covered by terrace gravels 

 and alluvium. 



South and somewhat west of the Sunshine anticline is a sharp 

 minor anticline whose axis trends about N35°W. This is separated 

 from the Sunshine anticline by a relatively shallow syncline in which 

 the lower part of the Cody shale is exposed. This syncline is largely 

 covered by the Wasatch, but in all probability it dies out rapidly in 

 the Cody shale both to the northwest and the southeast. The Frontier 

 is the lowest formation exposed at the surface in this fold. Here the 

 uppermost sandstone member of the Frontier is a white to gray, brown 

 weathering sandstone with some very well indurated layers. Casts 

 of Inoceramus and other marine lamellibranchia are rather numerous. 

 The east limb of this anticline dips 67°NE and the west limb 57°SW. 

 On the north the Frontier closes just as it disappears under the over- 

 lying Wasatch formation. 



Gooseberry Creek Anticline. — Southwest of the minor fold de- 

 scribed above, and separated from it by a sharp narrow syncline in 

 which the lower part of the Cody shale is exposed is the Gooseberry 

 Creek anticline. Gooseberry Creek cuts transversely across the center 

 of this fold, exposing the Cloverly formation in the center. On its 

 flanks are exposed the Thermopolis shale, Mowry shale, Frontier for- 

 mation, and Cody shale. This is a much sharper fold than the Sun- 

 shine anticline, but it dies out rapidly to the north. Its southern 

 limit is not known, as not far south of the area mapped it is covered 

 by the Wasatch formation. However, the Dakota sandstone, which 

 closes at both ends of the fold, plunges rather steeply both to the 

 north and south, indicating that this anticline, in spite of its greater 

 width, is shorter than the Sunshine anticline. 



This comparatively short fold is asymmetric, being much steeper 

 on the east than on the west, being in this respect the reverse of the 

 northern part of the Sunshine anticline. The east limb dips 73 °E 

 and the west limb 22°W. The trend of the axis is N 25°W, S 25°E. 



In the Mowry shales on the east limb a small amount of over- 

 turning and even slight overthrusting of 15 or 20 feet has taken place. 

 This overthrusting is confined to the Mowry shale, the massive Fron- 

 tier sandstones being unbroken. 



The larger folds along the southwest side of the Bighorn Basin 

 trend northwest-southeast and must have been produced by compres- 



