Distribution of Brachiopoda. — Foerste. 247 
Platystrophia lynx is very abundant in the Mount Auburn 
bed, but along this area it is found also in the Warren bed, 
usually near the middle of the Arnheim bed, but a short dis- 
tance beneath the Dinorthis retrorsa horizon. In the lower 
part of Lick run, opposite the mouth of Caesar creek, north- 
east of Lebanon, Ohio, Platystrophia lynx occurs 7 feet be- 
low the Dinorthis retrorsa horizon. Near Arnheim, Ohio, 
it occurs about 8 feet below Dinorthis retrorsa. At Wyom- 
ing, Kentucky, a massive, fine grained, argillaceous, blue 
limestone underlies the horizon containing Rhynchotrema 
deniaia and Leptaena rhomboidalis, and at various levels 
in this rock Platystrophia lynx may be found. Platystrophia 
lynx is associated with Leptaena rhomboidalis at this hori- 
zon at all points farther southward. At some of these, for 
instance at the locality west of Lebanon, Platystrophia lynx 
occurs both above and below this horizon. On the western 
side of the Cincinnati geanticline, a few specimens of- 
Platystrophia lynx may be found two or three feet above 
the Leptaena rhomboidalis horizon even as far north as the 
locality along the creek, about a mile south of Mount 
Washington, in Bullitt county, Kentucky, but farther north 
no specimens of Platystrophia lynx have been detected as 
yet in the Arnheim bed. As far as may be judged from 
the evidence at hand, Platystrophia lynx after a period of 
extraordinary development during the Mount Auburn 
period , was much reduced in numbers and disappeared 
northward, but continued to exist in southern Kentucky 
during the deposition of the lower part of the Arnheim bed. 
During the middle of the Arnheim period it increased in 
numbers and extended its range northward at least as far 
as Lick run on the eastern side of the Cincinnati geanticline, 
but on the western side it has not been found at this level, 
as yet, north of Mount Washington. 
No specimens of Platystrophia lynx were found at the 
Dinorthis retrorsa horizon, at Clifton, Tennessee, but at 
Newsom, about 15 miles southwest of Nashville, a single 
good specimen was found in association with four specimens 
of Rhynchotrema dentala in what is regarded, provisionally, 
as equivalent to the Arnheim bed. 
Another fossil, whose presence near the middle of the 
