Possible Algal Microfossils from the Late Pre-Cambrian of California

Abstract

SEVERAL organically preserved microbiotas in cherts of Pre-Cambrian age have been described during the past few years^1–10, some with structures such as cell walls and intracellular organelles intact^8,9. Pyrite and/or haematite replacement of possible Pre-Cambrian microorganisms, with loss of structural detail, has also been reported^10,11. Crystals of pyrite 5–10 microns in diameter and closely spaced along organic filaments “resembling a string of beads” are known from the Gunflint Iron Formation of Ontario, Canada¹⁰. “Chains of cells”, which our preliminary examination suggests are haematite crystals, were reported from the Belt “series” of Montana¹¹. We here describe similar crystalline chains interpreted as biological in origin from the late Pre-Cambrian Beck Spring Dolomite of southern California.