Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 243, part 1
Sedimentology and Ichnology of Paleozoic Estuarine and Shoreface Reservoirs, Morrow Sandstone, Lower Pennsylvanian of Southwest Kansas, USA

Fig. 30. Transgressive lag of gravel and fragmented shells separating facies G from the underlying paleosol siltstones of facies B (Fretz).