NON-CALCIFIED ALGAE FROM THE UPPER DEVONIAN OF THE HOLY CROSS MOUNTAINS, CENTRAL POLAND
Algae are preserved as carbonized remains of different length and width, often curved. The bigger forms possess a few dozen of centimeters in length and approximately one centimeter in width. Smaller stems or branches are preserved as stripes of a few centimeters in length and a few millimeters in width. In a better preserved specimens dense concentration of a smooth, long, not dichotomously divided hear-like filamentous structures can be seen creating broad strap-like thallus. Generally, incomplete forms are detected but some of them posses smoothly tapering endings which can be treated as natural endings(?). No holdfast or sexual organs can be recognized.
Because the filamentous character of those thallus remains can be found among various species of extent specimens of brown, green and read algae, it is hard to classify them even to the higher systematic level. Similar algae remains have been previously described from the Frasnian of Alberta (USA), but preserved as a much smaller forms and classified as a Type C and D without the precise systematic position.
The place yielding the fossilized algae (the Kowala Quarry) was situated on the southern shelf of Laurussia, where during the Frasnian/Famennian time basinal conditions prevailed. Then the presence, and concentration of macroalgal remains may indicate that algal fragments may have been swept from the adjacent shallower places during storms, or those types of algae preferred floating mode of life and during exceptional conditions (e.g. storms) part of them could sunk, and be preserved in badly oxygenated bottom waters.