At this time, most of what Sedgwick called "The English school of geologists" distinguished superficial deposits which were "diluvial", showing "great irregular masses of sand, loam, and coarse gravel, containing through its mass rounded blocks sometimes of enormous magnitude" and supposedly caused by "some great irregular inundation", from "alluvial" deposits of "comminuted gravel, silt, loam, and other materials" attributed to lesser events, the "propelling force" of rivers, or "successive partial inundations".