paper on volcanic intrusions; R.J. Walker et al, Igneous sills as a record of horizontal shortening: The San Rafael subvolcanic field, Utah paper on Clastic pipes; D.F. Wheatley et al, Clastic pipe characteristics and distributions throughout the Colorado Plateau: Implications for paleoenvironment and paleoseismic controls Geology, liquefaction, quicksand, earthquakes, injectites,