i86 
The Ohio Naturalist. 
[Vol. VII, No. 8, 
often argillaceous composition as well as the red muds, resulting 
from extensive weathering, suggest similar conditions of deposi¬ 
tion. The approximate correlation of these deposits is then as 
follows: 
INDIANA. OHIO. 
Sellersburg beds Delaware limestone 
Jeffersonville limestone ) 
Geneva limestone } Columbus limestone 
Northward in both states the line of division between these 
formations becomes less distinct and in the northern part of the 
southern Indiana area Dr. Kindle remarks that “associated with 
the loss of individuality of these two formations occurs a ming¬ 
ling of their two faunas which renders them indistinguishable as 
separate faunas.” 4 To a very limited extent the same is true 
in Ohio where we find species belonging to the Columbus lime¬ 
stone of central Ohio well up in the Delaware of the northern 
part, but the preponderance of Hamilton species in the upper 
formation is even greater in northern than in central Ohio. 
The full meaning of these similarities is rather hard to state 
definitely but they certainly indicate contemporaneous deposi¬ 
tion and more or less open communication during their forma¬ 
tion, and that the sea bordering the eastern shore of the Cincin¬ 
nati land area was not essentially different from that which 
washed the western shore of the same. 
SUCCULENT PLANTS OF OHIO. 
Nellie Ely. 
The typical succulents are characteristic of desert and saline 
regions. There are, however, some fleshy and watery plants 
which grow in shady and moist places, which show some of the 
peculiarities of typical succulents. The structures of the xero- 
phytic succulents are highly specialized to harmonize with the 
usual conditions of the desert. Thickening of the epidermis, 
the comparatively small number of stomata, the more or less 
globular form of the stem or leaves in certain species, and the 
development of special water-storage tissues are among the most 
striking adaptations to be found in the plant kingdom. 
Succulents may be divided into two groups according to their 
specialized parts. Leaf succulents, in order to restrict transpi¬ 
ration, reduce the surface of their leaves which become more or 
less cylindrical or globular in shape. These leaves have in their 
tissuse peculiar cells, called water-storage cells which serve for 
4. Ibid. p. 570. 
