946 The American Naturalist. [November, 
he will, after passing out of flat river bottom, cross a strip of 
level country about ten to fifteen miles wide, that forms a kind 
of shelf alongside the river bottom. After this one goes into 
the hills—topped with red-sandy clay, red-sandy or red-clay 
soils. These hills are the products of erosion out of a past plain, 
and Mr. L. C. Johnson compares them to the buttes of the 
west. Some of them rise rather abruptly, others gently ; some 
attaining a height of from 80 to 150 feet above the general 
level of the hill lands. One hill called Leatherman’s Mount- 
ain, is said by Mr. Johnson to reach an elevation of 700 feet, or 
about three hundred feet above the general level. The vege- 
tation of these hill lands is mostly oaks, where the soil is not 
very sandy, but when much sand is present, the short-leaf 
pine (Pinus mitis) abounds. 
As one proceeds south from Arcadia, at something like thirty 
miles distant from that place, the red sandy clays give place to 
pure white sands, that bear luxuriant forests of the long leaf 
pine (Pinus palustris), though as one nears Alexandria, which 
is 85 miles further south than Arcadia, the sand is somewhat 
redder, but still contains little or no clay. In the country whose 
surface is made up of these deep white sands, the lands wash 
badly, and hills rise very steeply to a height of 75 to 100 feet 
above their bases. These sandy hills are all clothed with an 
almost uninterrupted forest of that most majestic tree, the long 
leaf pine. It is absent only in the small “hollows” between 
| the hills, and in the calcareous prairie lands. 
Seattered through the southern part of Bienville Parish, 
through Winn, Grant, and Catahoula Parishes, are spots of 
calcareous lands, that are usually prairies of several acres in 
extent. These lands usually belong to the Jackson and Vicks- 
burg horizons, though the spot of the lime-lands in northern 
Nachitoches Parish belongs to the Claiborne, Ostrea sellaformis 
being found there in great abundance. There is a hill of crystal- 
line limestone near Winfield, La., that is Cretaceous. These lime- 
lands seem to present especially good conditions for the de- 
velopment of the land shells. By far the majority of the spe- 
cies of the land shells collected were found associated at one 
_ place or another with these calcareouslands. The need of lime 
