ABSTRACT
At the end of the XDC° century, some enigmatic microfossils found in “Precambrian” deposits from Brittany were described as radiolarians (Cayeux, 1894). This surprising discovery initiated the idea that radiolarians were amongst the oldest representatives of planktonic life on Earth. Further analysis o f the same material determined, however, that these “Precambrian” fossils were in fact microhystrichospheres or archaeomonadaceans of Palaeozoic age (Deflandre, 1949). Later, other siliceous microfossils found in Early Cambrian volcanogenic siliceous sediments from Kazakhstan were interpreted as possibly being radiolarians (Nazarov, 1973). However, due to their poor preservation, their identification as radiolarians remained questionable.
