see ee 
276 Cincinnati Society of Natural History. 
tion. Nor can there be any argument drawn from the distribution of 
the fossils, that will separate it from other Lower Silurian groups by 
stronger lines than those which distinguish groups in other formations. 
The word “Cambrian,” in its application to this group is not ad- 
missible, because it is part of the Lower Silurian. Beside, the word 
‘Cambrian,’ for want of proper definition, ranks for uncertainty, 
even in England and Wales, with the word “Taconic” in America. 
There are some who use such mongrel names as “Cambro-Silurian” 
and “ Siluro-Cambrian,” which have about as accurate significance, in 
geological nomenclature, as Cretaceo-Pliocene would have, or as 
Orthocero-Calymene would have in paleontology, if one should apply 
it to a trilobite found within an Orthoceras, or Platycero-Goniasterot- 
docrinus appled to a Platyceras attached to the vault of a crinoid. 
Or, a better illustration still, in order to settle all questions relating to 
Chetetes and Monticulipora just call the names Monticuliporo-Che- 
tetes, or Cheteto-Monticulipora. How absurd! 
The Calciferous Group.—This group was first defined by Lardner 
Vanuxem, in 1842, in the Geology of the Third District of New York. 
He defined and united into one division, the silicious layers above the 
Potsdam sandstone, with the “ Calciferous sandrock” or “ Transition 
rock,’ of Prof. Eaton, and the “Bark-like layers” of Eaton, or ‘‘ Fu- 
codial” layers of the early New York geologists, under the name of the 
Calciferous Group. 
fn New York, the lower part is compact and silicious, and graduates 
into the Potsdam below, the middle part is a sandy limestone having 
a shattered appearance, and the upper part is apparently a mixture of 
calciferous material with compact limestone. The thickness is from 
250 to 300 feet. It extends from New Jersey across New York into 
Vermont, where the prevailing character is that of a sandy limestone, 
compact and thickbedded, and having a thickness in the broken up 
mountain ranges of 300 feet. From New York it extends into Canada, 
where it is, generally, a granular magnesian limestone, covers several 
thousand square miles, and reaches a thickness of 450 feet. It occurs 
on the Mingan Islands, 500 or 600 miles to the northeast, and is finely 
exposed in Newfoundland, where it consists of definitely stratified 
limestone having a thickness of 2,000 feet or more. 
It occurs in the Lake Superior region, on the St. Mary’s, Escanaba 
and Menomonee rivers, and extends westerly across the State of Wis- 
consin into Minnesota. It is seen in the bluffs of the Mississippi, 
from the Falls of St. Anthony to the mouth of the Wisconsin river. 
le 
