Layers of rock that bend can produce a downward fold known as a(n)

Layers of rock that bend can produce a downward fold known as a syncline. This is the type of fold that occurs with the younger layers of rocks remaining closer to the center of the structure. Synclines can be recognized by the fact that the youngest layers of rocks always remain near the folds center.  

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.