Article: Algal tuft structures in stromatolites from the Upper Triassic of south-west England

Stromatolites in the Upper Triassic (Rhaetic) of south-west Britain contain lineations within (algal) laminae which are compared to filament tufts in modern algal mats. These Triassic tuft structures were formed by the clumping of highly motile micro-organisms displaying strong phototaxis, probably oscillatoriacean cyanophytes. Although such structures are common in modern algal mats they have not previously been recognized in ancient stromatolites. Their preservation in the Triassic is due to early lithification. Such fossil structures provide information on the nature of the algal community even though no actual algal remains are preserved.