Excavated face in an inactive gravel pit in Cache la Poudre River valley north of Greeley. A channel of overlying, finer-grained, darker-colored alluvium 2 (between 2-4 Ka) was eroded and then filled in the underlying, coarser-grained, lighter-colored deposits of alluvium 3. The lowest part of the alluvium 2 channel is at the white folding rule. Photo credit: Stephen Keller for the CGS.