30 November 2022


Posted by Callan Bentley

Another glimpse of sand on the beach at Esterillos Oeste, Costa Rica…

This time, I offer you a trace of an organism moving through the wet sediment:

Note the two parallel lines of tracks laid down by little feet, and the central groove that overprints them. It reminded me very much of this similar arrangement, from near St. Andrews in Scotland, but: (1) this is the underside of a bed rather than its upper surface, and (2) it is of a rather more substantial magnitude…

(The same pencil is used for scale in both of these images!)
The Scottish example is interpreted as a eurypterid trackway, but since eurypterids are now extinct, I’m not sure what made my Costa Rican example – a crab hauling a stick?