This middle member of the Fowkes Formation has the thickest and most
extensive outcrops. The Bulldog Hollow Member is exposed along the west
side of the basin.
Included rocks are green, white, and blue-green mudstone with ash beds,
green and buff claystone, and tuffaceous, limy sandstone. A high
percentage of the iron mineral, magnetite, occurs in the sandstone.
Conglomerate occurs as lenses.
The Bulldog Hollow Member has a gradational contact with the underlying
Sillem Member. The amount of volcanic material increases upward from the
Sillem, indicating an increase in volcanic activity during the
deposition of the Bulldog Hollow Member.