148 The American Geologist. September, i898 
contact phenomena along its northern edge. The older rocks 
with which it is in contact are nearly always highly changed 
from their original condition. The following localities ex- 
hibit the most conspicuous exposures of contact: 
T. 65 N. R. 3 W. At the western end of Loon lake the 
gabbro lies upon the graywarcke slate members of the Animi- 
kie. This is a sandstone and quartzyte. At the contact and 
for ten to fifty feet from the gabbro the quartzyte is com- 
pletely changed and consists of irregular, angular and in- 
terlocking grains of quartz, having a typical granitic structure. 
Hornblende and biotite occur in large plates and surround 
quartz grains as a matrix in a poikilitic manner. Other parts 
of the Animikie at this locality have been changed to a biotite 
schist. The gabbro has a uniform coarse grained texture. 
Akeley lake, T. 65 N. R. 4 W. Here the gabbro is found 
in contact with the iron bearing and black slate members of the 
Animikie. These members are entirely recrystallized by the 
effect of the gabbro. The iron bearing member forms a 
coarsely crystalline rock composed of quartz, pyroxene, olivine 
and magnetite. The black slate member was changed into 
biotite schist, and crystalline quartz rock. The carbonaceous 
matter was collected as graphite which occurs extensively in 
the contact zone. The gabbro of this locality is a uniformly 
coarse grained normal phase of the rock. 
T. 63 N. R. 8 W. South of Disappointment lake the gabbro 
is in contact with a conglomerate and beds of iron ore. The 
older rocks are entirely recrystallized though retaining their 
stratification to a remarkable degree. 
Sec. 30, T. 62 N. R. 10 W. In this locality large blocks of 
a quartzose pyroxene magnetite rock, like that at Akeley lake, 
occur in the gabbro two miles from its northern border. 
Birch lake, T. 61 N. R. 11 W. North of the lake the gabbro 
is in contact with quartzose pyroxene rocks, which extend 
westward and are found to be a part of the iron bearing mem- 
ber of the Animikie. (43, pp. 159-169.) Southwest of the 
lake the gabbro produced biotite schists at the contact with 
the Animikie rocks. 
Many of the quartzose, pyroxenic and olivinitic magnetites 
occuring at the preceding localities have been regarded by 
Bayley (41, Vol. H, p. 814), as peripheral phases of the gabbro. 
