1. n. [Geology]

A symbol plotted on a dipmeter log used to indicate dip angle and direction. The symbol, named for its resemblance to a tadpole (a toad in its larval stage of development) consists of a circle with a short line (or tail) extending from it. A solid black dot shows good data, while an open circle indicates a less reliable measurement. The circular part of the tadpole is plotted against depth on the y-axis and dip magnitude is on the x-axis. The tail extends in the azimuthal direction of dip; the azimuth measurement is displayed with north or 0° being up, east or 90° at right, south or 180°is down and west or 270° is left.