Finlay (1916) = Lytle and Glencairn Lytle- Page 8, The Lytle sandstone member, which is named from Lytle in the valley of Turkey Creek, consists of sandstone and intercalated beds of grit and shale. Its base is generally marked by a coarse massive sandstone 15 feet or less thick composed of prevailingly siliceous white, yellowish-brown, or bluish grains. The average diameter of these grains is about an eighth of an inch, but the largest fragments are an inch across. In some places, as near Colorado City, the base of the member consists of fine-grained white or cream colored sandstone 100 feet thick. The Lytle member contains pebbly beds at several horizons and scattered lenses of greenish or reddish clay near the top. The pebbly layers, which are separated by beds of fine grained white sandstone, are abundant in the uppermost 50 feet. The average thickness of the member is 145 feet. Glencairn page 8 The Glencairn shale member, so named from a tract of land a few miles north of Lytle, consists of dark shale and a little sandstone and is rather sharply separated from the Lytle member. The best section is in the railroad cut near Bear Creek. The base of the member consists of 12 feet of purplish-black shale, much cracked and broken, having veins of gypsum, the largest a quarter of an inch thick in the cracks.