the Copper-bearing Rocks of Lake Superior. 323 
_ same bed, of a species of Scolithus. The mass on Campment 
_ @ Ours is of the same color and friable character as the yellow- 
zontal, (fig. 2). It is succeeded in ascending order, by the fol- 
lowing series of beds:— __- 
Bluish-gray shales, interstratified with thin beds of yellowish compact 
limestone, presenting an escarpment over the sandstone. The fos- 
acuta, Sirophomena alternata, Rhynchonella plicifera, and a small 
| = __ undetermined Lingula, agit res eae ARM. Dee ge 
_ Measures concealed “ 
mpact limestone, in beds of from three to five inches 
x inches, un- 
cameratum, Cheirurus plewrexanthemus, and Leperditia Cana- 
ee ee ee te 
Ash-gray compact limestone, of the same character as the preceding, 
but still more fossiliferous. The beds contain Tetradium fibratum, 
brosa, Columnaria alveolata, Petraia profunda, Stro- 
Phomena aiternata, S. filitexta, Rhynchonella recurvirostra, Ambo-. 
nychia amygdalina, Cyrtodonta Canadensis, C. Huronensis, C. 
mytiloidea, Vanuxemia inconstans, Ctenodonta nasuta, Pleuroto- 
maria subconica, Eunema strigillata, Subulites elongatus, Ortho- 
ceras tenuifilum, O. Murray?, an undescribed Cyrtoceras, Asaphus e 
platycephalus, and Leperditia Canadensis, - ~ ~ ~ =~ = * fos 
The fossils of these limestones leave little doubt that they be- 
long to the Birdseye and Black River group; and the under. ying 
j Sandstones and other rocks, constituting the upper ve id 
cig series of Lake Superior, may thus represent the Chazy, Cal- 
Ciferous, and Potsdam formations, and be equivalent to the = 
bec group, with the black shales and limestones beneath 1%" iis 
&quivalency and the existence of an upthrow bringing the Que 
