296 American Geologist. ^^^^' ^^^^ 
"The small size of the Mesodon albolabris points to depauperization 
possibly under the influence of cold, or of insufficient food. The pres- 
ence of Succinea permits a general assumption of considerable mois- 
ture. It is true that Succinea obliqua is to-day found in not very moist 
places, but the aptitude of the organism is for wet spots, and it flour- 
ishes best under regional conditions of considerable annual precipita- 
tion. Patula altcruata is disposed to flourish under moist conditions, 
and generally will ivot endure a dry climate or position. Patula stri- 
atella may be safely regarded as a northern and semi-boreal species." 
"Conclusions of any diagnostic value cannot be made with security 
upon such slender representation of shells, but the impression left by 
them is that of rather boreal and wet conditions of life." 
In answer to a request, professor Gratacap graciously con- 
sented to examine a larger collection of shells. The forms 
most abundant in undisturbed upland loess in various direc- 
tion about town were selected for the purpose but those sent 
were all from the bluffs to the south and southeast. His 
determinations are as follows : 
Mesodon albolabris Say, fragile, immature, depauperate. 
Mesodon albolabris Say, with revolving striae destroyed. 
Mesodon albolabris Say, immature, weak, cold conditions. 
Patula alternata Say, color splashes, thin, depauperate, indication of 
cold. 
Patula alternata Say, color splashes ; probable burial or voluntary 
sepulture before long exposure. 
Helicina occulta Say, quite normal. 
Succinea obliqua Say, normal, flourishing individuals. 
Succinea obliqua Say, average forms but shrunken, cold conditions. 
Succinea obliqua Say, very small, pinched and starved individuals. 
Cast, enclosing Succinea. 
Commenting on them he says : 
"In regard to any light these specimens throw on the question of 
aqueous or aeolian conditions I must frankly say that they, to me, seem 
to offer no decisive evidence." 
But he also says : 
"The flamings and color patches on the "alternata" are certainly 
quite vivid and indicate burial. It does not seem to me that aeolian de- 
position of necessity should be extremely slow. Certainly dust storms 
of any continuance would make deposits of very considerable thickness 
in a short time. As regards "alternata," however, it may be recalled 
that the animal craves moisture and does not readily endure dryness. It 
also buries itself in captivity. The color marks are usually more strik- 
ing and deep if the animal has enjoyed normal moist conditions — and 
therefore it would be reasonable to suppose that the preservation of 
the 'flamings' indicates a normal habitat. Aridity would seem to be as- 
sured by the aeolian theory." 
