234 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii, 



In Texas abundant in the limestones of the Middle Cambrian, at 

 Packsaddle Mountain, Llano Count}'; at Morgan's Creek, Honey 

 Creek, and Coal Creek Canyon in Burnett County. 



In Wisconsin, Middle Caml)rian at Trempealeau, below the lifth trilo- 

 ])itc bed; also in the upperiuost horizon of the Upper Cambi'ian at 

 that locality; Middle Cambrian zone at Hudson, at bluff near city and 

 4 miles from Readsburg; Osceola Mills quarry in suburbs of village 

 near St. Croix River; Berlin; Winona; Alma; and Menominee. 



In Minnesota, 4 miles southeast of Lake City; River Junction, 

 Houston, 20 miles below Dresbach; Red Wing; Reads Landing, foot of 

 Lake Pepin; Minneiska. 



In Missouri, casts of this shell occur in the thin-!)edded magnesian 

 limestones 50 feet above the conglomerate series in St. Francois County, 

 collected b}' Dr. Frank Nason; at about the same horizon in Iron 

 County, in sec. 22, T. 8.5, R. IE., collected by Mr. D. K. Gregor. 



In Montana, Spring Hill Canyon, west side of Bridger Range; east 

 and west sides of Dr}- Creek above Pass Creek, Gallatin Valley; north 

 and east Gallatin River, near Hillsdale. 



In Idaho, Gallatin limestone 3 miles southeast of Malad City; also, 

 2 miles southeast of Malad City in limestone resting on the Flathead 

 sandstones. 



In Wyoming, Gallatin limestone on the divide at the head of Sheep 

 Creek, Teton Range; Crowfoot section, Gallatin Range; also on the 

 north slope of the Crowfoot Ridge on the south side of the Gallatin 

 Valley, and on the divide between Panther Creek and the Gallatin 

 River. 



As far as known the species occurs in association with the Middle 

 Cambrian fauna in Texas, Wisconsin, Minnesota, and Idaho. In the 

 Teton and Gallatin Ranges, Wyoming, however, it occurs at the upper 

 limit of the Cambrian. 



BILLINGSELLA DICE, new species. 



In general form and surface this shell is related to B. romingeri. It 

 differs from the latter in its strong dental plates. 



Formation and locality. — Lower Ordovician (?) The specimens of 

 this shell are from a drift bowlder found near St. Albans, Vermont. 

 The lithological characters of the matrix point to the arenaceous lime- 

 stones of the Phillipsburgh formation just north of the United States 

 and Canadian boundary as the source of the bowlder. 



BILLINGSELLA EXPORRECTA Linnarsson. 



Ortlxu expon-ecta Linnarsson, Bihang till K. Svenska Vet. Acad. Handlingar, 



III, 1876, No. 12; Brach. Paradoxides Beds of Sweden, p. 12, pi. ii, figs. 

 18-19; pi. Ill, figs. 20, 21. 



OHhis cxporrcrtd Kaysek, ('ainbrisihe Brach. von IJan Tung, China, Richthofen, 



IV, 1893, p. 35. 



