290 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Horizon and locality—Crown Point formation in New York: East side Val- 
cour Island, Sloop Bay, and Chazy, Plattsburg (15’) Quadrangle. 
Mingan formation (zone 5) on Bald or Mingan Island, Mingan Group, 
St. Lawrence River, Quebec, Canada. 
PETROCRANIA TRENTONENSIS (Hall) 
Plate 27, G, figures 15-17 
Crania trentonensis Hatt, Descr. new species Crinoidea and other fossils, p. 12, 1866; 24th 
Rep. New York State Cab. Nat. Hist., p. 210, pl. 7, figs. 11, 12, 1872; Pal. New York, 
vol. 8, pt. 1, pl. 4H, figs. 21, 22, 1893—WINCHELL and ScHucHERT, Geol. Minnesota, 
vol. 3, p. 374, pl. 20, figs. 36, 37, 1803. 
Type.—Hypotype: 116835. 
Horizon and locality—Martinsburg formation (Salona equivalent) in Vir- 
ginia: On Virginia Highway 617=910, 0.15 mile north of Green Mount Church, 
4 to 5 miles north of Harrisonburg, Broadway (15’) Quadrangle. 
PETROCRANIA sp. 1 
Plate 22,G, figure 14; plate 25,H, figure 23 
In the “Ottosee” facies near the base of the Lowville in the belt running along 
the Cumberland Front and in the high Chickamauga limestone in northwestern 
Georgia a small species of Petrocrania occurs on slabs in some abundance. Un- 
fortunately, all the valves in the National Museum collection show the interior 
only, thus making it unwise to describe the species. The form of the valves is 
suggestive of P. trentonensis. 
Figured specimens.—109776a, 109778. 
Horizon and locality.—Ridley formation in Georgia: On U. S. Highway 27 
just north of Chickamauga Creek, Kensington (T.V.A. 106-SE) Quadrangle. 
Dryden formation in Tennessee: Lone Mountain-Tazewell road, 14 miles 
northeast of Lone Mountain; road along Little Sycamore Creek, 4 mile north- 
east of west edge of Howard Quarter (T.V.A. 162-NW) Quadrangle; west side 
of the sharp loop on the road down Flint Creek, NW4 center subquad., Pow- 
der Springs (T.V.A. 154-SW) Quadrangle. 
PETROCRANIA ? sp. 2 
Plate 25, C, figures 8-10 
Species represented by a single brachial valve of small size; outline irregular ; 
beak not discernible ; both profiles broadly convex; posterior side the narrower. 
Interior with 2 large but indistinct muscle scars on the posterolateral extremities. 
Anterior with a short and low septum. 
Figured specimen.—109770. 
Horizon and locality—Edinburg formation (base of the Liberty Hall facies) 
in Virginia: 1.8 miles S. 4° W. of Bethel Church, 5.9 miles east of Harrisonburg, 
Harrisonburg (15’) Quadrangle. 
Discussion.—The specimen in question is a silicified valve in which the interior 
