catena

A term that would seem to be a legacy of the early Spanish explorers, catena is actually from the Latin for chain, and is used everywhere from theological tracts (Aquinas’s Catena Aurea) to planetary geology, where it describes a series of similarly sized impact craters. In the introductory soil science classroom, however, catenae really come into their own as a teaching tool, illustrating how a sequence of soils in a region can share the same parent material yet, due to the slightest variations in drainage and relief, differ radically in color, texture, smell, and pH—all the characteristics by which soil is measured. A catenary sequence drawn from the top of an incline or hill (with an auger) will usually bear little resemblance to a sequence drawn from the bottom of that same incline, forcing us to accept that topography isn’t just contour, but an indication of what’s going on beneath the surface as well.

Stephen Graham Jones