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IOWA ACADEMY OF SCIENCE Vol. XXIX, 1922 
left to represent the reticulum — traces of which are so faint that 
the character of the mesh is not clear. 
Specimen b is 203 mm. long and 135 mm. in greatest diameter. 
It has been partly flattened and distorted by pressure at time of 
burial ; parts of eight annuli are preserved ; they are less prominent 
and farther apart than in specimen a, due, in part at least, to the 
imperfect preservation. The surface of the specimen is nearly 
all covered with a black carbonaceous film except for patches of 
iron sulphide, presumably iron pyrites; the pyrite seems partly 
to coat the surface as a thin film intimately mingled with the 
carbon or just beneath it. On the metallic surface of the pyrite 
may be detected very fine vertical ridges, two or three in the 
space of a millimeter, and obscure traces of cross lines. These 
may represent the reticulum. 
Specimen c consists of a fragment of the rapidly expanding 
basal part of another individual. It shows parts of six annuli 
with long gentle lower slopes and short abrupt upper slopes. 
They average from crest to crest a width of nine millimeters. 
Fine concentric lines occur on the upper slopes of some of the 
rings and there are a few striae on the lower slopes at right angles 
to the lines on the upper slopes. These seem to represent what 
remains of the reticulum. The inner surface of the cavities or 
molds from which this and the other two specimens were taken 
would very likely show the pattern of the reticulum had they 
been saved by the collectors. The dimensions of specimen c are : 
diameter at smaller end 62 mm., at larger end 100 mm., height 
about 35 mm. 
Position and Locality: Upper Devonian, Lime Creek shales 
in the blue plastic clay some thirty or forty feet below the marly 
horizon at the pit of the Rockford Brick and Tile Company, 
Rockford, Iowa. Specimens a and b were obtained at this pit 
by Mr. C. L. Fenton who has kindly submitted them to the writei 
for study. Specimen c was collected at the same pit at the hori- 
zon of Lingula fragilis by Mr. C. H. Belanski. It is University 
museum number 2801. 
Except for some fine specimens obtained by Barrois in the 
Upper Devonian beds of Brittany, France, and described by 
Hall and Clarke in their Memoir, this is the only species reported 
from this horizon outside of the New York-Pennsylvania area. 
Paleontological Laboratory, 
State University oe Iowa. 
