DESCRIPTION OF THE BEDS 219 



are 1.421 feet thick, according to Woodruff,^ and just soutli of the Big 

 Popo Agie Eiver stadia measurements by the writer and his party showed 

 1,453 feet. No complete measurements were made in other places, but 

 the thickness seems to run about the same in the entire region studied. 



The contacl wiili i\\v ovei'lyiii.u formation, whicli in this region is the 

 Sundance, is usually covered; but on the west side oL' 'Table Mountain, 

 ? miles south of Lander, tlie exposure is good in a small valley. The 

 contact is one of disconformity, as evidenced l)y the weathered surface of 

 the Red Beds on which the sandstone of the Sundance was deposited. 

 The same phenomenon appears in the anticline near the Dallas oil wells, 

 but no other evidence was found at any place. 



The contact with the underlying formation is rarely seen, but on Bull 

 Lake Creek, 40 miles northwest of Lander, the exposure is excellent. 

 The beds at the bottom are of red shale, containing much pyrite; the 

 change to the uncJerlying Embar is merely change of color from red to 

 green, and sedimentation appears to have been continuous from the older 

 formation into the younger. ISTear Ed Young's house, on the Little Popo 

 Agie River, 16 miles south of Lander, a massive conglomerate up to 30 

 feet in thickness occurs at the contact in at least tAvo places. In neither 

 place was the red rock found immediately overlying the conglomerate, 

 but the situation was such as to leave no doubt concerning the relation- 

 ships of the conglomerate, and evidently a slight disconformity occurs 

 between the Embar and the Red Beds. 



The lower 800 feet of the Red Beds in the rea^ion near Lander is 

 largely dark red, shaly sandstone, extensively ripple-marked and becom- 

 ing more and more calcareous toward the top. Some of the beds stand 

 out as though made of thick-bedded sandstone, uniform in iexture, color, 

 mill thickni'ss for long distances; but on weathering these appear shaly. 

 .Vt about 800 feet from the bottom the incrcasins' amount of lime in the 

 water terminated with a deposit of from 1 to 6 feet of limestone, which 

 thickens away from the mountains. The limestone was not seen in the 

 region north of Rawlins, though it may have been present; but in the 

 next outcrops, about 25 miles southeast of Lander, it apjiears and extends 

 northwestward for at least 50 miles. The stone is magnesian. fine 

 grained and compact, and is locally designated as marble. The writer 

 has never found a fossil in il. \A'oodiiiff says: "Locally this bed is thin- 

 bedded and irregular, as if deposited from hot springs." " 



As it has very little pore space and is in the main non-crystalline, it 

 can not be secondary in origin. Tt shows no sign of being clastic. Tt is 



"BiiM. 4.'>2, U. S. Oool. Siirv.. p. IK. 

 *]U\\\. l.M', V. S. Cool. Siirv., p. I.''.. 



