Apart from the multitude of supposed fossil Algae described as " Fucoids " but usually not of Algal nature, and never presenting determinable characters, very little remains that can be referred to Palaeozoic Brown Algae.
Certain markings on slates and sandstones, such as the "fucoids" of Scandinavia and Scotland, the Phycoides of the Fichtelgebirge, Eophyton and other seaweed-like impressions, may indeed be the casts of fucoid plants; but it is by no means sure that many of them are not mere inorganic imitative markings or the tracks or casts of worms. Oldhamia, a delicate branching body, abundant in the Cambrian of the south-east of Ireland, is probably a calcareous alga, but its precise nature has not been satisfactorily determined.
The highest beds, consisting of quartzites, shales, marls and sandstones with the remains of fucoids, are found in the Jurjura and Shellata.
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