Sunday, April 25, 2021

Crania recta Brachiopod Fossil


Crania recta Plate 9 Figure 2 Mold of upper valve, with portion of shell attached, showing muscular scars.

The U.S. Postal Service just delivered a book I purchased from Willis Monie-Books of Cooperstown, New York USA. The book is called New York State Museum Bulletin 49 December 1901 Paleontologic Papers 2. It contains a number of papers including one called Marcellus (Stafford) Limestones of Lancaster, Erie Co. N.Y. by Elvira Wood.

Crania recta Plate 9 Figure 3 View of another specimen similarly preserved.

 She describes the new brachiopod species Crania recta on page 157-158.

"The three specimens obtained are all upper valves. Two are molds of the external surface with minute fragments of the posterior portion of the shell retained; the third shows the exterior. The former were attached to the interior and the latter to the exterior of the living chamber of Orthoceras.

Upper valve transverse, having the form of a flattened rim with sharply elevated central portion; beak subcentral. A shallow sinus, widening toward the front, extends from the beak to the anterior margin. Outline of the valve straight on the posterior side, regularly rounded at the sides, and slightly arcuate in front. Surface marked by fine lines of growth. Under a strong magnifier the surface is seen to be minutely granulose, a feature not visible under an ordinary hand lens. Posterior adductor scars are shown on a fragment of shell remaining. 

Lower valve unknown. 

The characteristic features of the species are the straight posterior margin and greater transverse diameter.

Measurements of three specimens are: 1) anteroposterior 5 mm, lateral 7.8 mm; 2) anteroposterior 5 mm, lateral 6 mm; 3) anteroposterior 4 mm, lateral 5.2 mm, depth 1 mm."

Crania recta Plate 9 Figure 1 The upper valve with outlines of dorsoventral and lateral sections.