Cylindricum Linck, 1949

Description: Vertical infilled tubes, 10-20 mm in diameter and approximately 60 mm long. May be found as scattered, isolated tubes (Fig. 22) or in small groups. The infilled burrows weather out as rods, often with a rounded base.

Discussion: Cylindricum differs from Skolithos in its greater diameter and shallower depth, and resembles burrows in Miocene and Recent river sands that are attributed to tiger beetles (see Frey 1975, fig. 2.1).