Both sides of the flippers and flukes are black.
Thus it is used of the purchase used in raising the flukes of an anchor to the bill-board; of a piece of wood or metal used to strengthen a sprung mast or yard; and of a plate of metal used, as in railway construction, for the strengthening of the meeting-place of two rails.
In this condition they remain encysted as immature flukes until eaten by their final host.
According to Strabo he was the first to invent an anchor with two flukes.
The Tertiary strata of Andalusia are specially noteworthy for containing the native silver of Herrerias, which is found in a Pliocene bed in the form of flukes, needles and crystals.
