76 The American Geologist. February. 1903. 
west by Cope, Newberry and Marcou and called Jurassic by 
them. The limestone and sandstone above mentioned there- 
fore can not be Cretaceous and undelie the Jurassic ; 1)ut must 
be of the same age as the Red Beds with which thev form an 
unbroken series. 
Age of the Red Beds. — The Red Beds of the west, on ac- 
count of their being non-fossiliferous and red in color, have 
been called Trias ; and even the Red Beds flanking the Jemez 
plateau at the Rio Chama and in the vicinity of Nacimiento 
have been called Trias by Cope for the same reason. Others 
have called them Carboniferous. They are conformable with 
the known Permian at Jemez ; and this Permian, in turn, lies 
conformable on the Carboniferous. They can not therefore be 
Carboniferous. There is no positive evidence that they are 
Triassic, though Cope, Newberry and Marcou referred them to 
that system. In speaking of the formation at Caiion Caugilon 
just north of the Jemez mountains. Cope says'*: "The sand- 
stone of the north half of Canyon Caugilon is Cretaceous 
number I, thickness 800 feet. Below it is the gypsum usually 
referred to the Jurassic, 50 feet, and doubtless inseparable 
from the brilliantly colored beds below (400 feet) which are 
stated by Hayden to be Jurassic beds. The hard sandstone 
underlying these is the upper member of the beds that corres- 
pond to Trias of the Colorado section." 
Since the survey from which Cope made his report was 
finished, many geologists have investigated the Red Beds in 
different parts of the west and have demonstrated that they 
can no longer be called Trias simply because they are red and 
non-fossiliferous. Fossils have been found in some localities 
which show that the lower portions, at least, of the Red Beds 
are Permian. 
In a letter to the writer bearing the date of January 25th, 
1900, Dr. C. L. Herrick says : "We have been fortunate enough 
to find a good series of Permian fossils in the lower Red Beds 
of southern New Mexico." The Red Beds in Texas and west- 
ern Kansas that were once called Trias are now conceded to be 
Permian, and the finding of Permian fossils by Dr. Herrick 
in the Red Beds of New Mexico is evidence of the Permian 
age of these rocks also. 
