1873: Live Frog found in Black Diamond Coal Mine
In 1873 at the Black Diamond Coal Mine on Mount Diablo, California, miners discovered a large frog patially embedded in a layer of limestone that had been exposed by a blast. The hole fitted the frog so well that it presented a perfect impression of its former resident. Both the frog and its tomb were brought to the surface, where the frog, evidentally bling and only able to move one leg, lived for just a day (of course, it was exposed to an explosion... so what could you expect?). The frog and its tomb were presented to the San Francisco Academy of Sciences.
The synopsis above is the legend as told by Frank Edwards in his book, Stranger Than Science (1959), and it is from his book almost all modern account of this matter now come from, which is a problem. In digging for more information on this event, I have only found two references from 1873 that could show it happened... well, kind of.
The first of these is a note from Appleton's Journal of March 15, 1873, which states that Mr. Cornwall, president of the Black-Diamond Coal-Mines, presented a frog to the California Academy of Sciences in San Francisco. Cornwall stated the frog had been found in the mine at a depth of 228 feet while the men were using pickaxes rather than blasting, and he had been unable to find the pieces from which it was taken. Appleton's Journal concludes the brief report by stating the circumstances were so suspicious as to not be worthy of notice.
The second article about the Black Diamond frog is a general release newspaper article from the Otago Witness, from New Zealand, dated April 12, 1873... about one month after the Appleton's Journal note on the matter. In this article we are informed that the frog was found embedded in sandstone 175 feet below the surface, it's form "perfectly preserved in the rock as if molded in soft clay." After initial release, the frog was very active; but over the next twelve hours it show a gradual decline in its abilities until it died, "from the effects of old age." The president of the coal mining company took the frog's remains to the Academy of Sciences in San Francisco.
So perhaps you see the problem: only two references, one against and one for, and with differing details. All that I can definitely say right now is that in early 1873 claims were in fact made that a frog was found in the Black Diamond Coal Mine... but everything else is up to debate. I will try to contact the Academy of Sciences to see if they ever received the frog, which may open a new line of inquiry for this little matter.