372 J. M. Safford on the Cretaceous : 
Its eastern outcrop is not well marked. It appears to extend — 
from 15 to 20 miles eastward from a straight line drawn through — 
the most westerly parts of the bluff. The bed is represented on 
the map and in the section by a dotted or broken line. (7,7) Tt 
will be seen that the narrow river-valleys of West Tennessee — 
cut this and the Bluff loam into sections. Ack 
8. The Bluff Loam.—This, the topmost of the bluff formations, — 
is generally a mass of fine siliceous loam, somewhat calcareous, 
and usually of a light ashen yellowish or buff color, but some- 
times lacking the yellow tinge. It is indistinctly stratified; con- 
tains land and fresh-water shells, and frequently oddly shaped 
calcareous concretions. It has in Tennessee a maximum thick 
ness of about 100 feet, ranging generally, however, from 30 to 
80. In the bluff at Memphis, it is from 40 to 60 feet thick, and 
presents in its lower part, along a well-marked horizon and ina 
vertical position, earthy ferruginous casts or moulds of what may 
have been the long tapering tap-roots of some tree. 
The loam rests directly upon the Bluff gravel, and its range 
and extent are shown upon the map by the spaces included his ; 
the broken lines representing the outcrops of the gravel, Its 
eastern limit, like the eastern outcrop of the underlying bed, 18 
with difficulty defined; both are alike given approximate are 
The following species of shells have been collected from 
formation : 
1, Helix appressa, Memphis. 6. Planorbis bicarinatus, Memphis. 
2. H. hirsuta, - 7. Cyclas,sp.t Z 
3. H. monodon, - 8. Amnicola lapidaria, . 
4. H. solitaria, Dyer county 9. Lymn 
5. HZ. profunda, Hickman, Ky. 10. Succinea, sp. ? 
“ 
low high-water mark of 
al beds ° 
sand, clay, gravel and vegetable matter of the ie Be 
om. Ido not propose to dwell upon it here. As a WHO © 
extent in Tennessee can be seen upon the map. (9,9.) 
'S This Journal, [2], x, 56. 
