Maryland Geological Survey 321 



about 7 mm., with a length of more than 3 inches, becoming extremely- 

 slender and attenuate towards the apex. These fossils usually appear to 

 have been subjected to maceration in the muddy sediment, and seldom 

 preserve any indication of surface markings. There are rare examples, 

 which present some evidence of obscure annulations or striae." Hall, 

 1879. 



This fossil occurs on the surface of slabs of dark or drab shale as flat- 

 tened acicular cones destitute of surface markings. 



Occurrence. — Romney Formation, Onondaga Member. Williams 

 Eoad, 3I/2 miles east of Cumberland. 



Collection.- — U. S. National Museum. 



[E. M. Kindle.] 



Family NAUTILINIDAE 



Genus AGONIATITES Meek 



Agoniatites expansus (Vanuxem) 

 Plate XLII, Fig. 6 



Qoniatites expansus Vanuxem, 1842, Geol. N. Y., pt. iii, p. 146, fig. 1 (non 



von Buch). 

 Qoniatites expansus Hall, 1860, Thirteenth Rep. N. Y. State Cab. Nat. Hist., 



p. 96, figs. 1, 2. 

 Qoniatites vanuxenii Hall, 1879, Pal. N. Y., vol. v, pt. ii, p. 434, pis. Ixvi-lxviii; 



pi. Ixix, figs. 3-6; pi. cix, figs. 7, 8. 

 Qoniatites vanuxemi Hall, 1888, Pal. N. Y., vol. v, pt. il. Supplement, p. 39, 



pi. cxxvii, figs. 3-6. 

 Agoniatites expansus Clarke, 1901, N. Y. State Mus., Bull. 49, pp. 124, 125. 

 Agoniatites expansus Clarke, 1903, N. Y. State Mus., Bull. 65, p. 573. 

 Agoniatites expansus Grabau and Shimer, 1910, N. Am. Index Fossils, vol. ii, 



p. 135, fig. 1388. 



Description. — Shell large, discoid, flattened on the sides and upon the 

 periphery in its advanced stages of growth; volutions of the spire about 

 three to four in specimens of smaller and medium size, and not determined 

 in the larger ones; umbilicus large and open, exposing all the volutions 

 of the spire. Living-chamber extremely large, occupying fully two- 

 thirds of the last volution, with capacity at least four times as great as 

 all the air-chambers together. Septa deeply concave, and with some 

 exceptions, regularly increasing in distance toward the outer chamber, 

 21 



