- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Describes erosion in falls of earth upon the roofs of London. The material must have fallen from a considerable distance, and whether forming mere pellets or splashes a few feet in diameter it developed a surprisingly uniform summit level of little more than one inch in height. An impermeable roofing foundation with a shape favoring run-off contributed greatly to erosion by rain water and the loam content washed out quickly leaving a gravel residue.