Orientation studies of graptolite rhabdosomes from five Ordovician localities in central Victoria show distributions whose X 2 values differ from random upwards of the 5 percent level. The phases of the first two harmonics identify the distribution with wave phenomena from a direction which agrees with the primary directional structures in the sediments. Under different conditions, the rhabdosomes may point up, down, or transversely with the current. Longer rhabdosomes are more reliable indicators than the shorter ones. The distributions indicate that Ordovician paleoslopes were generally northerly directed, the sources ranging from the southeast around to the southwest.

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