Typical lenticular deposit of pisolitic dolomite from the uppermost Yates
Formation. Note reverse
grading of coated grains. Pisoids have been attributed to algal growth, caliche formation, marine
spray-zone precipitation, and seepage-spring development. Roadside outcrop at hairpin turn on
New Mexico Highway 7 in Carlsbad Caverns National Park, Eddy Co., New Mexico.
Coin is 2.4 cm in diameter.
© Peter A. Scholle, 1999