Box 25, Folder 15: Paleontology Notes 6, Brachiopoda II

[blue ruled paper]

Genus Orthisina

Pict 4 p 57

[blue, ruled laid paper; worn embossing at u.l.: B & Co [sprigs over a basket of flowers on a table with B & Co in a rectangular impression]; handwritten page, verso, visible]

Orthis aequivalvis, Hall- [James Hall Jr. (September 12, 1811 – August 7, 1898) was an American geologist and paleontologist. He was a noted authority on stratigraphy and had an influential role in the development of paleontology in the United States.] Pal. N.Y. Vol. 1 p. 120 pl. 32 fig. 6.

Subrotund; valves almost equally convex; length nearly equal to the breadth; sides contracted just below the cardinal line, which is less than the greatest width of the shell; area narrow; foramen small; dorsal value differing from the ventral in the beak being slightly extended, and scarcely curved over the foramen; surface marked by about twenty rather sharp radii, with deep intermediate spaces; radii strongly marked entirely to the beak, and becoming bifid or trifid towards the middle of the shell.

L. 0.6 - H 0.6-

[blue, ruled laid paper; worn embossing at u.r.: B & Co [sprigs over a basket of flowers on a table with B & Co in a rectangular impression]; handwritten page, verso, visible]

Lower Silurian, Blue Limestone

Cincinnati Ohio.

[blue, ruled laid paper; worn embossing at u.l.: B & Co [sprigs over a basket of flowers on a table with B & Co in a rectangular impression]; handwritten page, verso, visible]

Orthis bella=rugosa, Conrad. Proc. Acad. Nat. Sc. 1843, Vol.1 p.33. Hall, [James Hall Jr. (September 12, 1811 – August 7, 1898) was an American geologist and paleontologist. He was a noted authority on stratigraphy and had an influential role in the development of paleontology in the United States.] Pal. N.Y. Vol. 1 p.118 pl.32 fig. 3.

Semi oval; length and breadth about an 7 to 8; valves almost equally convex, ventral valve with a narrow depression along the centre which becomes indistinct towards the margin, beak of the dorsal valve considerably extended beyond the cardinal line, scarcely incurved; surface marked by fine, close, radiating striae, which are equally bifurcated towards the margin and transversely marked by prominent imbricating squamose lamellae, which alternately advance and retreat in passing over the striae and the spaces between them - Less convex than O. subaequata.

L. 0.45 - H. 0.4-D. 0.2 -

[blue, ruled laid paper; worn embossing at u.r.: B & Co [sprigs over a basket of flowers on a table with B & Co in a rectangular impression]; handwritten page, verso, visible]

Lower Silurian

Mineral Point, Wisconsin. Middle Tennessee