ECHINODERMATA OF THE BRASSFIELD FORMATION 
27 
Abactinal area composed of numerous small plates. These 
plates are very small near the tips of the rays and gradually 
increase in size toward the disk, numerous plates on the disk 
equalling 2 mm. in diameter. Nothing is known of the arrange- 
ment of the plates except along the distal halves of the rays 
where the plates are aligned in slightly oblique rows, as indicated 
on rays A and B of the accompanying figure. Apparently five 
or six of these rows occupied the width of the ray between 6 and 
12 mm. from its tip. In the present state of preservation of the 
specimen, the larger plates, on and near the disk, appear to be 
irregularly interspersed with smaller plates. In the accompany- 
ing figure, the larger plates are shown best on the left side of the 
disk, between rays B and D. 
Nothing definite is known of the surface of the plates, but a 
few of them present the appearance of having been strongly 
elevated at the middle into a prominent node. 
Locality and position. The holotype was found about 5| miles 
east of West Union, l| miles east of the Stone Church, where 
the road crosses a small creek. Here the specimen was found 
in the Brassfield limestone at the top of a small fall immediately 
beneath the bridge, 30 feet below the base of the Dayton lime- 
stone, at about the same horizon as the holotype of Mesopalae- 
aster schucherti, although the latter was found miles west of 
Hillsboro, Ohio. 
Remarks. This specimen is of interest chiefly on account of 
its occurrence in the Brassfield formation. At the time of its 
discovery it appeared scarcely worth collecting. In outline it 
closely resembles Schuchertia laxata Schuchert, but it is distinctly 
larger and the plates on the disk appear to have been much more 
irregular in size. If these plates were strongly nodose centrally, 
this alone would be sufficient to distinguish it from the few spe- 
cies of Schuchertia hitherto described. 
The possibility of the plates being nodose centrally is sug- 
gested by an anomalous specimen (fig. 7 on plate II) found, 
associated with Brockocystis nodosarius, in the lower part of the 
Brassfield formation, on a hill-crest a mile northeast of the center 
of Manchester, Ohio. It is not known even that this specimen 
