Peneplains of the Ozark Highland. — Hershey. 25 
Boulders of nepheline rocks were found many years ago 
in the region north of lake Superior.* Dr. A. C. Lawson dis- 
covered rocks containing the mineral in the Rainy River dis- 
trict, towards the western boundary of the province, some 800 
miles west of the eastern outcrops.! It would thus seem that no 
really large area of the Archaean in this part of Canada is with- 
out the presence of the nepheline-bearing series. These out- 
crops whether they be considered of Laurentian or Huronian 
age, may be all looked on as having come originally from the 
same magma. Many of the districts, however, in which these 
high alkali-holding rocks occur cannot be said to be character- 
ized by the presence of these alone. Large areas of rocks 
holding a high percentage of alkaline earth metals are of just 
as common occurrence. This is especially true of those areas 
in the extreme eastern and western parts of Ontario and the 
western part of Quebec. At localities on either side of the 
boundary between these two provinces, anorthosytes, includ- 
ing among others the well known Morin area, occur in large 
masses, and from the fact that corundum occurs in some of 
these as well as in the nepheline-holding rocks, there seems to 
be little doubt that these rocks whose bases, in addition to 
alumina, are essentially the alkalis, sodium and potassium, and 
those whose basic constituent in place of the alkalis is chiefly 
calcium, are the products of one magma. 
PENEPLAINS OF THE OZARK HIGHLAND. 
By Oscar H. Hershey, Bragdou, Calif. 
The Ozark highland comprises all of the mountain coun- 
try of Arkansas, the eastern portion of Indian Territory, and 
most of the hill-country of Missouri south of the Missouri 
river. On the north and west it is bounded by the long east- 
ward slope of the "great plains" and the Upper Mississippi 
region ; on the east by the Illinois depression and the Missis- 
sippi embayment country, and on the south the sloping plains 
of Cretaceous and Tertiary strata stretch from its borders to 
the gulf of Mexico. It is separated into two somewhat dis- 
tinct uplifts, by the long, narrow Arkansas basin, which is a 
*Geol. Can. 1863, p. 480, and Reports for 1846-7. 
BtiU. Univ. cm., 1890. 
