Fig. 2From: A new method to determine volume of bromalites: morphometrics of Lower Permian (Archer City Formation) heteropolar bromalites a Spiral heteropolar bromalite morphololgy, relatively closely spaced turns concentrated towards one end. b Spiral amphipolar bromalite morphology, blunt ends with wider and regularly spaced turns running along the entire length (redrawn from Hunt et al. 1994). Orientation is based on Hunt and Lucas (2012)Back to article page