| This is a rather rare trace fossil called Helicodromites mobilis. It is a horizontal helical spiral. As can be seen when sectioned, the spiral produced off-set circular sections are clearly visible in this example. That section is not central so three of the spiral sections are cut longitudinally. H. mobilis occurs in deep-water muds, but also in shallower settings as long as the seafloor is quiet and muddy. |
