It's the shape of a Syncline, only bigger."
"Flowing Gold"
Rex Beach
When folding at length takes place along the axis of the elongated Syncline of deposition, the stresses find relief probably for some hundreds of miles, and the region of folding now becomes compressed in a transverse direction.
"The Birth-Time of the World and Other Scientific Essays"
J. (John) Joly
Thus we find that the ocean floor is depressed into a Syncline along the western coast of South America; a trough always parallel to the ranges of the Andes.
"The Birth-Time of the World and Other Scientific Essays"
J. (John) Joly