3. Phosphatic calculus containing a nucleus of uric acid, sawed through to show concentric layers.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
Osmotic growth gives us fibrous silicates, Phosphatic nodules, corals, and madrepores; it also gives us formations which remind one of the "atolls," calcareous growths rising like a crown out of the water.
"The Mechanism of Life"
Stéphane Leduc
As the older White Crag, presently to be mentioned, contains similar Phosphatic nodules near its base, those of the Red Crag may be partly derived from this source.
"The Student's Elements of Geology"
Sir Charles Lyell