40 7"/" 1 American Geologist. Jan. lsei 
bonate found in nodules, but it is desseminated throughout the 
mass. A quantity of the soil, freed from an}' nodules that might 
be therein, treated with hydrochloric acid shows the characteristic 
effervescence. A little barium hydrate makes one sure that the 
gas is CO,. The frequently occurring calcium nodules are gener- 
ally oval, but are sometimes lenticular in shape. As in the Loess 
many of these nodules seem to have been formed by the decay 
of bulb-like roots: calcium carbonate replacing the matter of 
the root. Indeed, not uncommonly may we observe a specimen 
in which there has not been complete change. Tn such an instance 
part of the nodule will plainly be calcium-carbonate while the 
other part still retains its fibrous character. 
Calcium-carbonate may be seen in threads or filaments pene- 
trating the ground. Generally these threads are nearly vertical. 
It would seem that to this phenomenon the vertical cleavage of 
these beds may lie ascribed. At least this is one factor that must 
be taken into consideration. A cliff once perpendicular manifests 
a tendency to retain its shape. These perpendicular, or approxi- 
mately perpendicular, lime filaments seem to be the result of two 
causes. First the solubility in water of the carbonate of lime. 
By water it was distributed throughout the soil following the 
capillary tubes. The passage 1 of the calcareous waters in these 
tubes would result in an approximately vertical deposition. This 
accounts partially for the roughness so often seen in the filaments 
themselves. Tn the second place the decay of rootlets and their 
replacement by lime may be the cause of the filaments that pene- 
trate the soil in a more nearly horizontal direction. These fila- 
ments determine cleavage much as mica does schistosity. 
The fossils of this formation show a striking similarity to those 
of the Loess. Indeed, a group of typical Loess fossils placed 
side by side with those from the upper beds of the Loup river 
region, would be distinguished from them with difficulty. . The 
species are identical. The characteristic creamy appearance of 
honafidi Loess fossils is present. The most common forms arc : 
S ccine<i avara ; S, lineata ; S. verrilli; Zonites limatvl us „• 
Helix striatella ; Pupa blandi ; Vallonia pulchella ; Helicodiscus 
lineatus ; Heliciiia occulta ; Carychium exiguum. From these it 
will be seen that it is impossible to draw a sharp line of demarka- 
tion between the formation under discussion and typical Loess, on 
a basis of paleontological evidence. 
