The Galena and Maquoketa Series. — Sardeson. 21 
divided into two main groups, those with feldspar and those 
without this mineral, and the former are called (jneisses. This 
usage makes gneiss a niineralogical and structural term ; 
mineralogical in that it contains feldspar, structural in that 
it is foliated. If the origin of the gneiss is determinable it 
has the original rock name added as a prefix. Thus a sec- 
ondary foliated conglomerate is called a conglomerate gneiss. 
a foliated granite is a granite gneiss. When the word gneiss 
is used alone it represents a foliated feldspathic schist of un- 
known origin. 
Down to the end of the last century geology was a collec- 
tion of hypotheses and sacred theories of the earth. Its stu- 
dents then began to observe and record facts, and later to 
form theories based on such observed facts. The study of 
the igneous rocks passed through a similar course of develop- 
ment. The study of the ^lletamorphic rocks is now passing 
through such a course and it has entered the descriptive 
stage. It is now at the point reached by general geology in 
the time of Lyell. and reached by the study of the igneous 
rocks in the year 1870. 
The study of the crystalline schists, both of Archsean and 
post-Archtean time, now becomes the great field for work and 
all over the world students are trying to trace their origin and 
formation. 
Washburn College., T(rpeka, Kansas. 
THE GALENA AND MAQUOKETA SERIES. 
By F. W. Sardeson, Minneapolis, Minn. 
Part II. 
New Classi^fjcaiion . 
In the first part of this paper it has been shown that the 
local classifications of the Maquoketa and Galena series are 
discordant, and that a more complete and generally applica- 
ble system, which will embrace the elements of truth contained 
in each, ought to be substituted. The entire succession of 
strata that go to make up the Galena and Maquoketa together, 
is divided into about fourteen easily recognizable beds, that 
are, as a rule, co-extensive and continuous, and that are the 
component parts of all the locally designated series, forma- 
