REVIEWS 657 
The Lower Carboniferous is well represented, the western bound- 
ary being approximately the Neosho River. The beds are continuous 
with those of northwestern. Arkansas and southwest Missouri. The 
subdivisions recognized are the Eureka shale, Boone chert, Fayetteville 
shale, Batesville sandstone and the Boston group. 
The rest of the Carboniferous is subdivided into Lower Coal 
Measures, Upper Coal Measures (with two groups, the Cavaniol or 
coal producing, and the Poteau or barren) and Permian. 
The remainder of the paper is taken up with lists of fossils, some 
descriptions of new species, and a short economic chapter. 
The restriction of the term Ozark to the northern part of the 
uplifted region of Missouri and Arkansas is noticeable. It is, no 
doubt, convenient to distinguish the northern, slightly folded part 
from the southern, trans-Arkansas portion, and to designate the latter 
the Ouachita region. The latter term will be generally used. This 
should not, however, be to the exclusion of some other name for the 
whole of the elevated area. The use of Ozark in the restricted sense 
as has been done, without giving any geographical reason, at once 
arbitrarily subdivides the region. The uplift, or dome, is believed to 
be a great geographic unit, having a definite history that covers the 
Ouachita district the same as the more northern area. Froma geo- 
graphic standpoint the close folding has no especial influence in the 
general development nor in determining its broad physiographic 
nature. 
If the two districts are really distinct in their present aspects, 
when viewed from the genetic and geographic points of vantage, it 
should be shown that their development is in no way connected, that 
the history of each has been different, that their present physiognomies 
are of diverse origin. This has not been done as yet; and no attempt 
appears ever to have been made in this direction. 
On the other hand all the published materials and the known facts 
seem to point to a very different course of events. After the Carbon- 
iferous the region between the Missouri and Red rivers was apparently 
subjected to orogenic movements— intense and local in the south, 
moderate and regional in the north. The whole region was then 
planed down during the Cretaceous or Tertiary, perhaps, practically 
base-leveled, so as to form part of the great peneplain of the Missis- 
sippi valley. The closely folded area appears to have been planed off 
in the same way as the broad flexures. Subsequent elevation of the 
