90 G. M. DAWSON ON BORINGS IN 
Peter sandstones. Its thickness (50 feet) is somewhat less than that assigned to the same 
bed to the south. This in Minnesota is stated as 125 feet; in Iowa, 80 feet, and in 
Wisconsin, from 80 to 100 feet. The St. Peter sandstone has not elsewhere been recognized 
in Manitoba, and there is, therefore, no local term of comparison for this and the 
underlying Cambro-Silurian beds. 
If the stratigraphical positions assigned to the foregoing beds are correct, beds 17 to 
20 both inclusive, with an aggregate thickness of 110 feet, must occupy the position of the 
Lower Magnesian limestone, equivalent in age to the Calciferous of the New York section. 
This limestone in Iowa and Wisconsin, has a thickness of 65 to 250 feet. In Minnesota it 
is described as a cream-colored magnesian rock, but toward the top it is frequently sandy, 
and with beds of greenish shale. At Rosenfeld no limestone occurs, and we, apparently, 
have instead a littoral formation directly overlying the subjacent Laurentian, and 
marking the limit at this place of the Lower Magnesian Sea. 
No sufficient supply of fresh water was met with in this well, but instead, a flow of 
brine was encountered. A small flow of brine was found below the limestone numbered 
10 (30 feet in thickness), a second flow beneath the heavy limestone bed (No. 14) and 
when the St. Peter sandstone (No. 16) was reached, the supply increased four-fold, and 
formed a flowing well, which has, I believe, continued to give issue to large quantities of 
salt water ever since. Mr. Swan states that it rose in a pipe to a height of 18 feet above 
the surface of the ground, which is three feet below the level of the railway grade. 
The most interesting feature in this connection is the great geological age of the rocks 
from which this brine comes. It appears not improbable that the shoaling of the Cambro- 
Silurian sea evidenced by the widespread littoral deposit known as the St. Peter sandstone 
resulted in the enclosure of salt lagoons in this portion of the interior basin, while it 
merely produced an increased land area further south in Iowa and Wisconsin. 
The brine is of a quality well adapted for the manufacture of salt, and might be 
concentrated by solar evaporation and finally evaporated in pans. It has been examined 
and is reported on by Mr. G.C. Hoffmann, in the Annual Report of the Geological Survey 
for 1885 (p. 13 mM). Mr. Hoffmann states that it contains but a small amount of deleterious 
salts, and gives the following as its composition for 1,000 parts by weight :— 
Chloride of BOtASSIUME 2217 eee eee dora RC 0.4179 
1 Sis hibbnissatiosanbe Oéba0un os dadonudohoghdomoocds oono- ehersk Al 
cs Calcium: nm immune corcenestesceeepanclens 0.3982 
i Magnesiume--- crc eee badd 0000 1.7225 
Sulphate offliimet--:".-cereeere-ce-checeec-s--cte-ce--cene 4.1511 
Borate: OL SOUS s,sicleto:ccszsvarctetaleleleletopereteteteteiave Soccer Suis ee eters ee traces. 
Carbonate Of Lime’ «saci ss west iect 4) ooeevedect en mess eee ce 0.0777 
we TrON scierie acereesrcLem ee re NET TEE Re traces. 
Bromide of Magnesium-:-2".-""-2er-e-.e- re: cree undt. 
Todide of Magnesium........................... voce cece voce cers undt. 
Another point of interest brought out by this boring is the comparatively thin 
covering of Paleozoic rocks which here overlaps the Archæan, and the very gradually 
shelving character of the surface of the latter westward. The slope of this surface, in a 
westward direction, from the last low Archzean exposures on the Lake of the Woods being 
