THE KIMMSWICK AND PLATTIN LIMESTONES 
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estimating the length of the cranidium. The facial suture curves 
abruptly downward, 5 mm. from the neck furrow, for a distance 
of 1.2 mm., thus limiting the frontal lobe of the glabella laterally 
with nearly parallel parts of the facial suture. Here the width 
of the frontal lobe is slightly over 5 mm. Viewed from above, 
the anterior outline of the frontal lobe, as far back as the ante- 
rior margin of the palpebral lobes, appears rather evenly convex. 
Viewed from in front, or from the side, the anterior part of the 
cranidium rises abruptly for a height of 1 mm., then curves rap- 
idly backward, attaining its maximum height of 2 mm. about 
on line with the anterior pair of glabellar furrows. Except 
along the frontal lobe, the glabella is only moderately convex, 
especially posteriorly. The palpebral lobes are 4.5 mm. in 
length, and extend as far back as the neck furrow. The poste- 
rior margin of the glabella is distinctly defined by an abrupt 
though very slight lowering of that part of the glabella forming 
the neck segment. The median tubercle on the neck segment is 
almost invisible. 
There are three pairs of glabellar furrows. Of these the 
middle pair is the longest. They are 2 mm. in length, and are 
separated by a distance of 2 mm. Both furrows are slightly 
curved, with their convex sides facing forward. Their outer 
termination is slightly in advance of the inner one. The ante- 
rior pair of glabellar furrows are about 1 mm. long, and are 
separated by a distance of 2 mm. They also are slightly convex 
toward the front. The posterior pair of glabellar furrows are 
slightly over 1 mm. in length; they are separated by a distance 
of almost 3 mm., and they are more convexly curved than either 
of the other two pairs of furrows. All three pairs of furrows con- 
sist of smooth lines, scarcely 0.1 mm. in wddth, in their present 
condition appearing as slightly darker lines contrasted wfith the 
whiter adjoining parts of the cranidium. 
The surface of the cranidium is marked by minute granules 
which become larger toward the margin of the cranidium. 
Under a microscope the granules are seen to be elongated trans- 
versely. Anteriorly, their upper surface slopes gradually down- 
ward. Posteriorly, the slope is more or less abrupt, often being 
