246 
FRAMEWORK OF ARIZONA 
cal history. With sorne inconsequential changes the divisions are 
designated by geographic names that are widely known in the 
region. The recently proposed title, Chinle Formation, for the 
entire succession is unfortunate; and besides this term is an exact 
synonym of Dolores Formation of the neighboring parts of Colo¬ 
rado. Were it not for this fact Gregory’s name might be pos¬ 
sibly retained as a serial title. 
The lower portion of the Triassic section is the part which 
yields the silicified woods so abundantly, for which reason it is 
designated by Ward the Lithodendron Member. Petrified forests 
occur also at other horizons, so that this title is not really distinc¬ 
tive. 
Jurassic rocks in northern Arizona form the grandest, most 
curiously wrought, and gorgeously colored relief features on the 
face of the earth. Painted Desert, Pictured Cliffs, Rainbow Can¬ 
yon, and Vale of Fire, are only a few of the many local names 
expressing the unmatched character of the scenery. Thick, mas¬ 
sive sandstones form long lines of lofty cliffs across the deserts, 
or, when detached, pass into gigantic battlements, unscalable pin¬ 
nacles, and cathedral spires that in the distance impress one with 
the approach to some great and populous city. There are no 
architectural masterpieces on the globe that at all compare with 
these natural structures. 
The four terranal units that compose the succession aggregate 
more than 2,000 feet in thickness. The basal Wingate sandstone 
is well described and pictured by Dutton. Todilto is Gregory’s 
name. Navajo, as a formational title, is preoccupied; and if the 
name La Plata is to be preserved it should apply to the upper 
great sandstone. The serial term Zunian is also Dutton’s desig¬ 
nation. 
The Early Cretacic section of southern United States and north¬ 
ern Mexico, designated by Hill as the Comanchan series, finds 
perhaps maximum development in southeastern Arizona and 
northern Sonora, and presents a terranal pile more than a mile in 
height. Despite its disguise under totally new and uncorrelatable 
nomenclature, the Bisbee section is readily paralleled with that 
commonly recognized in central Texas. 
Of the half dozen terranes distinguishable in the state the Co¬ 
chise sandy limestone (or lower part of the Mural limestone of 
