the chert at the ranch NE of camp. Where the strike turns westward I found a nonfossiliferous limestone in the Fountain and in a higher horizon found the crinoidal limestone. Strike N. 30˚ E. forming a syncline next to the foothills with axis approximately E., N limb steep, dip about 30˚ bearing S 5˚ W. Dip of S limb very gentle. Red Mt. Occupies base of syncline. ((visible from US 287)) Section E of Red Mt. Where strike changes to west ((drawing in field book)) Section through Red Mt. Where road swings around west of Red Mt in a valley, following the creek, To the N, W and S the sedimentaries have been removed unless it be the base of the Fountain, leaving a gently sloping plain, sloping from the west to the creek bed. We have now traced the chert horizon near the base of the sedimentaries from Wyoming to the place where the strike turns westward toward Red Mt. , finding brachiopods frequently most of the way. Also traced the lower