162 Copper Mines of Lake Superior. (April, 
went thither, to find all his recent unfinished work washed 
away. But on arriving at his work the following day, and 
finding it precisely as he left it, and hearing from his men 
that the sea had been all the time of his absence quite 
undisturbed, this unexpected information was to him just as 
marvellous as the phenomenon itself in Cattewater. 
The only possible cause of the disturbances of the sea 
this day, on the northern as well as on the southern coasts 
of Devonshire and Cornwall, and at the Scilly Isles, appears 
to be local submarine vertical shocks, not rising higher 
than the bed of the sea. 
These phenomena are never, as I consider, occasioned by 
undulatory earthquakes, but only by vertical shocks. During 
the earthquake at Antioch, on the 3rd of April, 1872, “‘so 
long as the wndulatery motion continued, no houses fell, but 
as soon as vertical jerks set in, a large part of the town was 
in a few seconds a heap of ruins.”*  Providentially these 
vertical shocks, proceeding from the deep interior of the 
earth, do not generally rise higher than the basins uf lakes, 
or the bed of the sea. Thus, on the day of the great 
earthquake of 1755, whilst only one shock was perceived on 
the surface of the mines in Derbyshire Peak, five smart 
ones were felt sixty fathoms undergroundt. On the same 
day, not only Lochness and other lakes in Scotland, but 
even ponds in England, were violently agitated without any 
perceptible shock in their neighbourhoods. 
III. THE NATIVE. COPPER MINES’ OF LDARS 
SUPERIOR. 
By JAMES DouGLas, Quebec. 
ae Jesuit fathers who, in extending the domain of 
Christianity two centuries ago, explored and described 
parts of the American continent, which are still 
almost as wild as then, likened Lake Superior to a relaxed 
bow on whose string rests an arrow, the north or Canadian 
shore being the bow, the south or United States shore the 
bow-string, and the arrow the promontory of Keweenah, 
which, protruding from the south shore far across the lake, 
divides its waters almost into halves. This promontory, 
* Times of July 30, 1872. 
+ Phil. Trans., 49, p. 398. 
