200 Systematic Paleontology — Middle Devonian 



Spirifer sculptilis var. marylandensis n. var. 

 Plate XIX, Figs. 14-16 



Desa'iption. — Bather more than one-half of the dorsal valve and its ex- 

 ternal impression were foiind in the Maryland Collection. These speci- 

 mens show eight angular plications on one side of the mesial fold which 

 is bifurcated by a furrow, the surface is strongly marked by conspicuous 

 imbricating, concentric striae, while the cardinal angle is mucronate with 

 somewhat corrugated surface. These specimens differ from the figures 

 and description of S. sculptilis in having a more mucronate cardinal 

 angle and a larger number of plications, eight on a side instead of from 

 three to five. 



The specimens were sent to Prof. Schuchert who returned them 

 labeled Spirifer sculptilis. They were also examined by Dr. Grabau who 

 sent me the following notes : " They come nearest to S. sculptilis. Too 

 many plications. It is more mucronate which is a primitive character 

 with this group of Spirifers, since they are mucronate when young. It 

 has more plications than normal which is an advanced character. Either 

 new species or variety of S. sculptilis." It does not appear to the writer 

 advisable to base a new species upon this imperfect material : but on 

 account of the divergence from the normal forms of the species it is re- 

 garded and described as a variety. 



Length, 15 mm. ± ; width, 44 mm. ±. 



Occurrence. — Eomney Formation, Hamilton Member. East side 

 Warrior Mt. east of Push. 



Collections. — Maryland Geological Survey. 



Genus AMBOCOELIA Hall 



Ambocoelia umbonata Conrad 

 Plate XX, Figs. 1, 2 



Orthis umbonata Conrad, 1842, Jour. Acad. Nat. Sci., Phila.. vol. viii, p. 264, 



pi. xiv, fig. 4. 

 Ambocoelia umbonata Hall, 1860, Thirteenth Rep. N. Y. State Cab. Nat. Hist., 



p. 71. 

 Ambocoelia umbonata Hall, 1867, Pal. N. Y., vol. iv, p. 259, pi. xliv, figs. 7-18. 



