OF PLANORBIS AT STEINHEIM. 93 



PI. denudatus. This last was very carefully collected, and there is no doubt in my own 

 mind, that it came from this formation, but though I sought diligently for specimens, I 

 could not find another. Above this we find Formations b, c and d, running together, 

 and consisting of layers of clay containing the fish remains. 



Formation "e," Little Pit. 



The lower part of this formation consisted of the same brown porous limestone drift as 

 formation e in the Old Pit, and the fossils of the lower part also agreed very closely 

 with those of that formation. The upper part contained a large admixture of the ordi- 

 nary friable shell-sand, and a somewhat distinct fauna. 



Lower Part. 



PI. minutus, PI. costatus, and PI. denudatus were particularly abundant, with PL dis- 



coideus. 



Upper Part. 



PI. discoideus, and PI. trochiformis are abundant, and with them numerous specimens of 

 the form of the young, known as rotundatus. 



rormation "f," Little Pit. 

 The prevailing fossils here, as elsewhere, were PI. trochiformis and PI. discoideus. 



East Pit, Section 3. 



This section was taken on the south side of the Pit, and continued as far down 

 as possible by a hole dug to the fish-layers of formation e. Any attempt to penetrate 

 this, though made here in two places, was frustrated by the influx of water. 



Formation " e," East Pit. 

 This consisted of clay in layers containing the usual fish fossils, but no shells. 



Formation "d, e," East Pit. 



This is very thick, and consists of layers of shell-sand of greater or less density, but 

 otherwise not distinguishable. They have the same lumpy character and brown color of 

 the corresponding formations in the Old Pit. PI. discoideus was abundant. 



PI. minutus and costatus were also abundant. PI. triquetrus was also found. A 

 broken specimen or two of oxystomus was found, a fact which was carefully ascertained. 



Formation " f ," East Pit. 



This formation is naturally divided into three parts just in the southwest corner of the 

 sandpit, where one hole was dug, by streaks of clay interpolated between the three thicker 

 layers of shell-sand. PI. discoideus is particularly fine in the lowest, but generally not 

 very large. The usual spiral transition forms are not very abundant, the large majority 

 being of the deeply channelled sulcatus form. A few also are smooth, but none of them 



