View to the south from top of Cerro de los Cuates (Hill of the Twins) in 1932. Note that tributary of Rio Puerco in center of view is a discontinuous arroyo, that is, it is incised in its upper reaches (left side of view) and unincised further downstream.
(Hunt 251)

Retake of Hunt 251; 7/2/98. View south-southwest from top of Cerro de los Cuates. Rio Puerco in foreground. This view is very interesting because the Puerco is only slightly incised in Hunt's view, but is fully incised at present. This shows unequivocally that the Rio Puerco did not incise from its mouth headward as has been argued in the past, since both upstream and downstream portions were incised before this time. This view is just upstream of the confluence of the Rio Puerco and Arroyo Chico. Arroyo Chico dumps large amounts of sandy sediment into the Rio Puerco, and this may be the reason that this portion of the Puerco was not incised at this time.
35° 36' 30" N, 107° 10' W, 35 mm lens.

Close-up of part of retake of Hunt 251; 7/2/98.