MICHIGAN ACADEMY OF SCIENCE. 
Ill 
This northward extension of (lie 
great 
Cincinnati 
uplift has been 
more emphatically anticlinal than it is now, up to the close of the 
Corniferous period. The evidence of this is perceptible at a glance at 
the cross-section map: the Devonian surface at the Wayne county end 
of the section stands 30 feet higher than the maximum elevation 
(560 A. T.) of Silurian dolomite, and 25 feet higher at the Essex county 
end of the section. Not only so but the Corniferous deposit is bowed 
up in the center at either end of the section, and crevassed over its 
central area at Sibley where the maximum of thrust has been exerted. 
It may be that the higher part of the anticline — across the Detroit 
river distance — stands at a lower elevation than it once did. The con- 
clusion is the same in the one case as in the other — there is a relatively 
lower anticlinal structure now than there was at the close of the Sil- 
urian age. 
As that Silurian surface is now, Crosse Isle, as traversed by this 
section at all events, reposes in a minor syncline of the greater anti- 
cline. on a surface Cower than the rock bottom of the two channels of 
Detroit river on either side of it, east and west; whilst the river, in its 
main channel, traverses the highest part of the anticline. 
These are the ascertained elevations along the line of cross-section, 
from west to east, with distances between successive points for which 
the elevation is quoted (i. e., Elevation of Silurian dolomite surface as 
hitherto accepted) : 
1. The Sibley section, to about middle of the Trenton channel of 
Detroit river : 
508.8 ft., (900 ft.,) 503,2 ft., (1,200 ft.,) 489.G ft., (2,200 ft..) 
519.0 ft., (1,600 ft.,) 538.0 ft., (?,000 ft.,) to 543.0; 
2. The Crosse Isle section to Ballards Reef in main channel of De- 
troit river: 
543.0 ft., (2,600 ft.,) 532.0 ft., (6,000 ft.,) 528,0 ft., (4,200 ft.,) 
to 550.0 ; 
3. The main Detroit river section, eastward from Ballards Reef: 
550.0 ft., (2,200 ft.,) 548.0 ft., (2,400 ft.,) to 560.0 ft.; 
4. The Amlierstburg quarry section, from the east side of Detroit 
river channel : 
560.0 ft., (5,800 ft.,) 515.1 ft., (2,100 ft.,) 482.0 ft., (1.400 ft.,) 
542.6 ft., (1,000 ft.,) to 575.7. 
Evidence of another section. In an investigation like this in which 
so much has continued in doubt, it would be manifestly unfair not to 
present every vestige of evidence that has direct bearing. Therefore let 
another cross-section be here introduced. This section, from a point on 
the new Livingstone Channel, northeasterly across Bois Blanc island to 
a point some 10,800 ft. distant, will serve to illustrate again the relation- 
ship of the Anderdon beds to the Sylvania Sandrock and all that lies 
between and above the Sylvania. 
At a point in the new channel west of the south quarter of Bois 
Blanc there was found to be a light deposit of white sand resting upon 
bedrock. This was all scraped off by the dredges in cleaning up the 
°River bottom elevations obtained from U. S. Government: Detroit River Improvement Survey. 
Crosse Isle elevations furnished by Professor W. H. Sherzer, from Survey publications. Sibley arid 
Amherstburg elevations obtained by the Solvay Process Company’s Survey. 
