1685 (pre): Live Toad found in Lime-Stone
According to Robert Plot, in an account of the event he published in 1686, a physician at Bath, England, named Dr. Pierce wrote a letter to the Philosophical society of Oxford describing the discovery of a living toad in a block of lime-stone.
The stone in question had been laid as a step stone for passengers in the middle of a cartway. A croaking noise was "being a long time heard" near the stone, and a search of the area turned up nothing; finally it was decided to break the stone the sound seemed to come from. Inside was found a cavity containing a toad as large as a man's fist, which hopped around "as if it had been bread [bred] in a larger room." Plot notes that the account does not mention how long the toad lived.
Plot gives as his source the Letter Book of the Philosophical Society of Oxford. Mar. 17. 1684/5 and Apr. 11. 1685... I shall try to find copies. It should be noted that Plot's own book was published in 1686, so the report from the Philosophical Society was recent news at the time he published.