Mysterious falls of frogs or toads from the sky are among the most iconic of all Fortean phenomena. Less well-known, but just as inexplicable, are cases of trapped frogs or toads that are found alive when solid rock or masonry is broken open. At one time such occurrences were a mainstay of popular folklore, as described by Jan Bondeson in Fortean Times a few years ago (Toad in the Hole, FT221:38, April 2007). The heyday of the subject was between the late 17th and early 19th centuries -- just when the idea of testing theories via practical experimentation was coming into vogue. The "entombed toad" theory is ideally suited to testing by experiment, and numerous amateur naturalists rose to the task... though generally in a clumsy and unscientific way.
Buckland's experiments, as described in the Fortean Times article, were pretty rigorous. He used two types of rock, limestone and sandstone, and made twelve cavities in each. A live toad was sealed into each cavity using glass plates and clay. The blocks of stone were then buried for a year, after which they were dug up and examined through the glass plates. The toads that had been sealed in sandstone (which is non-porous) were all dead, whereas at least some of the toads sealed in limestone (which is porous) were still alive. The limestone block was re-buried... but after another year the remaining toads were all dead. Buckland concluded that it was impossible for toads to survive long periods of incarceration, and that therefore the popular accounts must be erroneous. In the Fortean Times article, however, Jan Bondeson suggests that there were flaws in Buckland's experimental method and that his conclusion was more pessimistic than it ought to have been.