2 8o The American Geologist. November, 1903. 
and indications of large swamp land areas are exposed on 
Cibicu creek and in the vicinity of Fort Apache. As evidence 
that the country reached the swamp stage the writer found 
several specimens of Lepidodendron, and one whole tree of 
the species, Catamites cannaeformis. The group belongs to the 
coal-measure series as is attested by its fossils : Spirifer camer- 
atus, Prod net us seinireticnlatus, P. costatus. Lepidodendron, 
Calamites cannaeformis, etc. 
The exposures of this group are restricted for the most part 
to the bench lands and canyon-like slopes of the inner lowlands 
of all the streams in their middle and lower courses from the 
White mountains west to Cibicu, from which place they ex- 
tend around the Ellison dome in a wide belt to the "rim" of 
the Tonto basin. The southern prolongations of the Mogollon 
mesa are also usually capped with this formation near their 
terminus. Several small patches also occur in the vicinity of 
Globe. 
The Aubery Group. — The interstream spaces of all the 
streams in their upper course as well as the south front of the 
Mogollon range and the Cibicu divide, where not covered with 
later deposits are capped with 280 feet of calcareous sandstone 
followed by 500 feet of soft red and gray shales, interrupted 
by sectile limestone. The Aubery limestone occurs in one lo- 
cality — at the head waters of the Cibicu and Canyon creeks. 
The rocks of this group are usually non-fossiliferous ; but 
fossils enough were obtained [Athyris subtiUita, Productus 
punctatus, Spirifer caincratus, Productus, and Bellerophon] to 
identify it as upper Carboniferous. 
The Cretaceous (?). About twenty-six miles northwest of 
Fort Apache near Forestdale a coal outcrop is exposed, which 
seems on lithological grounds, to be the same as the Fort Union 
or Laramie coal of New Mexico. The extent of this coal series 
is not known to the writer as it is almost everywhere covered 
with later deposits. 
The Tertiary. — After the deposition of the Laramie the 
country was elevated and much eroded. Then another period 
of deposition set in, the deposits of which correspond in lith- 
ological character to the late Tertiary of New Mexico, though 
it is quite possible that the period of deposition covered a much 
longer time. It is quite probable that the deposition has, in the 
