Colin Hayter Crickmay (1899–1988) was Canadian

geomorphologist Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or ...

known for his contributions to

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

and hillslope

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

. Influenced by the observations of the

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

Eleanora Knopf Eleanora Frances Knopf ( Bliss; July 15, 1883 – January 21, 1974) was an American geologist who worked for the United States Geological Survey (USGS) and did research in the Appalachians during the first two decades of the twentieth century. ...

he coined the concept of unequal activity to describe the great disparities that can between stream erosion near stream channels and apparently unchanged uplands, and between headwaters with limited erosion and the more active middle and lower courses of streams. Crick did also coin the term panplanation to describe a

planation surface In geology and geomorphology a planation surface is a large-scale surface that is almost flat with the possible exception of some residual hills. The processes that form planation surfaces are labelled collectively planation and are exogenic (chi ...

s thought to be formed by lateral stream migration.

References

1899 births 1988 deaths Canadian geographers 20th-century Canadian geologists Geomorphologists 20th-century geographers {{Geologist-stub