196 Systematic Paleontology — Middle Devonian 



The Maryland specimens have about twelve clearly defined plications 

 which is found on comparison to be the number on some of the type 

 specimens from New York. Dr. John M. Clarke examined specimens 

 from the Maryland Eomney and stated that they were probably Spirifer 

 tullius. 



Length, 14 min. ; width, 20 mm. 



Occurrence. — Eomney Formation, Hamilton Member. Eun at 

 Hancock east of Catholic church; on Hancock-Harrisonville Eoad about 

 2 miles north of Hancock; along Flintstone Creek in Gilpin; B. & 0. E. 

 E. cut at Hancock Station, W. Va. 



Collections. — Maryland Geological Survey; New York State Museum. 



Spirifer angustus Hall 

 Plate XIX, Figs. 8, 9 



Spirifer angusta Hall, 1857, Tenth Rep. N. Y. State Cab. Nat. Hist., p. 164, 



fig. la text. 

 Spirifera angusta Hall, 1867, Pal. N. Y., vol. iv, p. 230, pi. xxxviii A, figs. 23-32. 

 Spirifera angusta Keyes, 1891, Johns Hopkins Univ. Circ, vol. xi, p. 29. 

 Spirifer angustus Hall and Clarke, 189?., Pal. N. Y., vol. viii, pt. ii, pp. 31, 39, 



pi. xxiv, figs. 14-17. 

 Spirifer angustus Schuchert, 1897, Bull. U. S. Geol. Surv., No. 87, p. 381. 

 Spirifer angustus Clarke, 1903, N. Y. State Mus., Bull. 65, p. 308. 

 Spirifer angustus Grabau and Shinier, 1909, N. Am. Index Fossils, vol. i, 



p. 330, fig. 420b. 



Description. — Shell ■with depressed pyramidal outline; great lateral 

 extension with attenuate and acuminate cardinal angles; valves very un- 

 equally convex with finely plicate surface. Ventral valve proportionally 

 very deep, forming nearly the entire thickness of the shell ; cardinal area 

 extremely elevated and inclined forward, the height nearly equal to the 

 length of the valve; delthyrium about twice as high as wide and grooved 

 on the sides. Dorsal valve slightly convex; mesial fold low and narrow; 

 cardinal area vei'y narrow. Surface marked by about forty-four or more 

 fine, simple and rounded plications on each valve, few of which reach to 

 the beak. 



The Maryland specimens are mostly external impressions found in- 

 frequently in arenaceous shales and consequently quite imperfectly pre- 

 served. They clearly show, however, the high cardinal area and long 



