A collective name (pl. karren) for the shallow channels formed by solution on exposed limestone. Kluftkarren are enlarged joints; rillenkarren are very closely spaced small runnels; small radiating rillenkarren are the overflow of surface solution pans. Rinnenkarren are both longer and deeper, as much as 10 m in length and 0.5 m in depth. They may develop as a result of coalescence of small channels. Their walls are sharp, in contrast with the large, rounded hollows known as rundkarren. The types of karren can be explained as the results of the solution process under different hydro-dynamical behaviour (Ferrarese et al. (2003) Geomorph. 49, 1–2).