SCIENTIFIC SUMMARY, 
105 
specimen is 250 millimeters; tlie greatest width of the body is 110 
millimeters. 
Lignite found in the Cretaceous Formation of the United States of 
America. — Mr. N. H. Winch ell, in a letter to Mr. Dana, published in 
“Silliman’s American Journal” (October 1875), says that an interesting 
discovery of lignite in the extreme northern portion of Minnesota has just 
been made. Explorations have been carried on during the summer by 
private parties in search of coal, and a hundred pounds of what was taken 
for coal were brought to Duluth from a point between Vermilion and Rainy 
lakes. Similar exploration has revealed the lignites of the Cretaceous at a 
number of other points in Minnesota, extending from near the Iowa State 
line to the central portion of the State. Mr. Kloos has given an account of 
a u Cretaceous basin in the Sauk Valley ” in “ Silliman’s American Journal,” 
and Mr. Meek identifies it a3 the Fort Benton by the few fossils that were 
gathered. Inferentially the Cretaceous has been extended over the most of 
Minnesota, and even into the State of Michigan (“ First Annual Report of the 
Geological Survey of Minnesota, 1872 ”), but this discovery not only shows 
that the Sauk Valley is probably not an insolated “ basin,” but also that the 
Cretaceous beds did extend, prior to the drift, at least, if they do not now, 
over the entire State from north to south. He has an account also of a 
probable Cretaceous outcrop in the state of Winconsin from Prof. Frank H. 
Bradley, but it has not been identified authentically. 
The Climate of the Poles, Past and Present, may not seem a very geolo- 
gical subject, yet it is one of the most interesting in the whole range of 
geological studies. A very valuable paper on this question has been con- 
tributed to the “ Geological Magazine ” (Nov. 1875), by Prof. Nordenskiold, 
in which he says that we now possess fossil remains from the polar regions 
belonging to almost ail the periods into which the geologist has divided the 
history of the earth. The Silurian fossils which McClintock brought home 
from the American Polar Archipelago, and the German naturalists from 
Novaja Semlja, as also some probably Devonian remains of fish found by the 
Swedish Expeditions on the coasts of Spitzbergen, are, however, too few in 
number, and belong to forms too far removed from those now living, to 
furnish any sure information relative to the climate in which they have 
lived. Immediately after the termination of the Devonian age, an extensive 
continent seems to have been formed in the polar basin north of Europe, and 
we still find in Beeren Island and Spitzbergen vast strata of slate, sandstone, 
and coal, belonging to that period, in which are imbedded abundant remains 
of a luxuriant vegetation, which, as well as several of the fossil plant- 
remains brought from the polar regions by the Swedish Expeditions, have 
been examined and described by Prof. Heer of Zurich. We here certainly 
meet with forms, vast Sigillaria, Catamites, and species of Lepidodendra , &c., 
which have no exactly corresponding representatives in the now existing 
plants. Colossal and luxuriant forms of vegetation, however, indicate a 
climate highly favourable to vegetable development. A careful examination 
of the petrifactions taken from these strata shows also so accurate an agree- 
ment with the fossil plants of the same period found in many parts of the 
Continent of Central Europe, that we are obliged to conclude that at that 
time no appreciable difference of climate existed on the face of the earth, 
