Phosphatic microfossils, notably conodonts, are composed of crystallites of calcium phosphate (apatite) embedded in an organic matrix. There is one type of stratigraphically significant phosphatic microfossils (conodonts); but fish teeth, of less practical utility, are found in some marine strata. | Phosphatic microfossils, notably conodonts, are composed of crystallites of calcium phosphate (apatite) embedded in an organic matrix. There is one type of stratigraphically significant phosphatic microfossils (conodonts); but fish teeth, of less practical utility, are found in some marine strata. |