PLATE IX — Continued 
Fig. 13. Strophomena acuta. A, lateral view, with indication of curvature of 
pedicel valve. Schuchert collection. Spring Valley, Minnesota. Richmond 
group. See also plate Vll, Fig. 3 A. 
Fig. 14. StropJiomena planodorsata. A, lateral view, with indication of the curva- 
ture of the pedicel valve; B, view along hinge area. Mannie clay, forming upper 
part of Richmond group, a quarter of a mile northeast of Fly, beyond the home of 
R. S. Elam. See also plate VI], Figs. 4 A, B. 
Fig. 15. Strophorneyia nutans. Lateral view of pedicel valve, showing contour of 
interior. Blanchester division of Waynesville. Oregonia, Ohio. See also plate 
X, Fig. 2 A. 
Fig. 16. Stropho7ne7ia nutans. Lateral view of pedicel valve, showing contour 
of interior. Clarksville, Ohio. Blanchester division of the Waynesville. See 
also plate X, Fig. 3 B. The convexity of the interior outline of the valve is slightly 
exaggerated. 
Fig. 17. Stropho7nena fluctuosa-occidentalis. A, brachial valve; B, lateral view, 
with indication of curvature of pedicel valve; C, interior of pedicel valve; D, 
interior of brachial valve. Richmond group, at Spring Valley, Minnesota. 
Copied from Minnesota Geology, vol. Ill, plate XXXI, Figs. 14, 15, 16, 17. 
PLATE X 
Fig. 1. Strophomena vetusta-precursor. A, Brachial valve. B, Pedicel valve. 
C, Interior of pedicel valve. Two miles southwest of Clarksville, Ohio, on Pen- 
quite Run, south of the pike to Middleboro. Blanchester division of the Waynes- 
ville. 
Fig. 2. Strophomena 7iuta7is. Three interiors of i)edicel valves. A, from Ore- 
gonia, Ohio; see also plate IX, Fig. 15. B, C, from the same locality. Blanchester 
division of the Waynesville. 
Fig. 3. Strophomena nutans. Not the typical form, but approaching Stropho- 
7nena concorde7isis in general appearance. A, B, C, D, interiors of the pedicel 
valve. Stony Hollow, northwest of Clarksville, Ohio. Blanchester division of 
the Waynesville. 
Fig. 4. Strophomena higgmsportensis. Interior of pedicel valve. Same speci- 
men as Plate 11, Fig. 3 B. Stony Point, east of Higginsport, Kentucky. Hori- 
zon unknown, but probably low in the Eden. 
Fig. 5. Orthoceras tyronensis covered by Derniato stroma tyronensis. A, High 
Bridge, Kentucky; B, nearly 2 miles northwest of Bryantsville, Kentucky, 
where the road turns northward and descends into a ravine. Tyrone member. 
Fig. 6. Acidaspis, species? Cephalon, imperfectly preserved; magnified 1.8 
diameters. Same specimen as that on Plate Vlll, Fig. 7. Number 9581, Faber 
collection, in Walker Museum, Chicago L^niversity. Lowry, Ohio. Exact hori- 
zon unknown. 
Fig. 7. Plectambo7iites rugosa-clarksvillensis. A, B, C, three interiors of 
brachial valves; D, interior of pedicel valve. A, southeast of Oxford, Ohio; 
B, Concord, Kentucky; C, exact locality unknown; D, east of Weisburg, Indiana. 
A, Clarksville division of the Waynesville; C, probably the same horizon; B, D, 
lower part of Liberty member. 
Fig. 8. Lingula procteri-versaillesensis . Brachial valves. A, older individual. 
B, younger form. Versailles, Kentucky, along the railroad to Frankfort. LTpper 
part of Paris bed. 
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