2i6 Bulletin of Laboratories of Denison University voi xi.j 
rise to more bitter controversies in recent years than has the 
Permian. The fact that the Permian is essentially a transition 
period accounts for much of this lack of unanimity of opinion, 
while the scarcity of fossil remains increases the difficulty of 
accurate correlations. Some geologists have sought to escape 
these difficulties by abandoning the Permian system altogether, 
merging it with the Carboniferous. But the fine development 
of this system in various localities, and especially in the Texas 
beds in this country, shows that the Permian is a great and 
widely distributed system, even though the scarcity of palaeon- 
tological evidence often renders it difficult of identification. 
Palaeontologically the Permian is most closely related to 
the Palaeozoic rocks, and most geologists have followed Mur- 
chison in regarding it as belonging to the Palaeozoic era. The 
fact that Marcou and others have classed it as Mesozoic has been 
explained as the result of a mistaken idea that Murchison in- 
cluded in his Permian a large part of the Triassic.^ 
Stratigraphically the Permian is more closely allied to the 
Carboniferous in some localities, and to the Triassic in others. 
In some portions of the west it would appear that there had 
been continuous sedimentation from the Carboniferous through 
the Permian into the Triassic. Without entering further into 
the discussion of the correlation of the Permian with the Palae- 
zoic or Mesozoic, we prefer to follow the lead of those who 
place it in the former era. 
Permian in Russia and India. 
In 1841 Sir Roderick Murchison carried on extensive studies 
of the rocks of Russia, and proposed the establishment of the 
Permian system, named for the ancient kingdom of Perm, to 
include the later Palaeozic rocks. This system is well defined 
and extensively studied in Europe. In India, Waagen has made 
an extensive study of the Permian, and described it more elab- 
orately than any other writer. He divides the system into three 
groups, — Permo-Carboniferous, Rothliegendes and Magnesian 
1 Notes on the Geology of Northwestern Texas, W. F. Cummins, 4th Ann. 
Rep. Geol. Surv. of Texas, p. 213. 
