JVeu" Features in Geology of Jlinnesota. — Wiuchtll. 41 
SOME NEW FEATURES IN THE GEOLOGY 
OF NORTHEASTERN MINNESOTA.* 
By N. H. WiNCHELL, Minneapolis. 
When the data that have been gathered during the hist fif- 
teen years relating to the geological structure of the north- 
eastern part of the state came to be put together, in an effort 
to classify and map them for a final report, it was discovered, 
that there w^ere certain vacua in the series of facts which we 
could not fill, and some points on which we had not enough 
information to warrant final report. It was for the purpose 
of supplying some of this lacking information that a small 
party was organized last September for the purpose of review- 
ing some of the rock outcrops which had already been exam- 
ined. The results of this review are quite important and in- 
teresting. They are divisible into four parts, viz : 
1. The nature of the transition from the crystalline schists 
to the Laurentian. 
2. The nature and relations of the Stuntz conglomerate of 
Vermilion lake. 
3. The nature and position of the coarse conglomerate in 
the Puckwunge valley, near Grand Portage. 
4. The nature of the contact of the Saganaga granite on 
the Ogishke conglomerate at Saganaga lake. 
I shall speak of the first three of these, and shall leave to 
Dr. Grant an explanation of the contact of the Saganaga 
granite on the adjacent conglomerate. 
1. The udture of the transition from the crystalline schists 
to the Laurentian. 
Under the term Laurentian have been included, in Minne- 
sota, two ditfei-ent rocks, or formations, in the same manner 
as in many places in North America, viz., (1) an acid cr^'^s- 
talline schist evincing definite and unmistakable evidence of 
direct derivation from a sedimentary' rock without having 
suffered fusion, or displacement from the position it original- 
ly occupied with relation to adjoining strata, and (2) a rock 
which is massive, or simply leaved by some cause into sheets 
of a homogeneous character, the sheets themselves being mere- 
ly separate layers of an apparently massive rock. The term 
*Read at the December (189G) meeting of the Minnesota Academy of 
Natural Science. 
