SINGULAR OCCURRENCE AT SEA.  -   MR. DOBIGNY, of the firm of DOBIGNY, RHETT and Co., Bahia, writes
 
"I arrived on the 25th November at Liverpool, after a most tedious and long voyage from Bahia, in the three-masted schooner "Seminole", CAPTAIN JOHN MCINNESS.
 
Myself and wife and a German lady named DENTZ were the only passengers.  When about mid-Atlantic, on an exceedingly calm day, with scarcely a breath of wind stirring, and as nearly as possible about two p.m., the atmosphere suddenly became most oppressive, and the barometer fell so rapidly as to make the captain apprehensive that some violent gale would speedily ensue.
 
After giving the necessary instructions for the safety of the ship, we all waited coming events with minds as easy as circumstances would allow.
 
Probably half an hour so passed, when suddenly, without a moment's warning, with a noise so appalling, so deafening as to defy description , the sea, as near as we could guess, within a quarter of a mile astern of us, was lifted up to an immense height in the shape of a sugar loaf, and when the gathering of the waters had attained its extreme limit, the descent was made with a roar and a turmoil to which even Niagra bears but a slight resemblance.
 
The agitation thus occasioned all but swamped us, and had we not held on by anything within reach which happened to be secure, we should all most assuredly have been washed overboard.
 
Half an hour later, a moderate breeze sprung up, and all evidence of the recent commotion had ceased.
 
CAPTAIN MCINNESS is at a loss to account for what was as novel to himself as to every one else on board;  and the only form of conjecture which presents itself to us is that some submarine volcano had become active."
 
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