Geology studied by:

GAGEL, C., 1912, STUDIEN UBER DEN AUFBAU UND DIE GESTEINE MADEIRAS. I:
ZEITSCHR. DEUTSCH. GEOL. GES., V. 64, P. 344-491

Cavalum (or Cavalém) Legend

The Caves of Cavalum, near the village of Machico at the Madeira Island, are huge caves digged at the basalt rock that people say are the dwelling of a monster. 
Cavalum is a devil under the form of a big horse with bat wings that expels fire through the nostrils.
It is still possible on stormy days, to hear the urros and patadas of the Cavalum ecoing through the walls of the caves.
Although some say that this is only the eccoing of the thunders, people asserts that is the monster that was made to stay there against his will. 
According to the legend, when the Cavalum was free, the beast knogked at the door of a church to speak to God. When God asked him what did he want, cavalum told Him he wanted to propose a chalange: the monster wanted to destroi the whole village, church included and he wanted to see if God, that was already a bit old, had the strengh to stop him. God sent him away telling that he had no patience to such jokes. But the cavalum, thinking that he had been honest warning Him, gathered the wind and clowds and these woke up a bit storm that felt terribly over the village. On the top of the clif, the Cavalum relinchava happily. God, envolvido nas suas mantas in front of the firplace, did not moove thinking that the Cavalum soon will get bored with his brincadeira. But the storm grew stronger and the people, atemorizado, saw houses and fields being arrasados. Even the crucifixo flew through air taken by the wind by order of the insolente Cavalum. It was then that God started to get mad and decided to finish that childish provocação. His first reaction was to make that a boat fownd the crucifixo. Then he called the sun that showed up at once, afastando the clowds, the wind and the thunders. The sky went blue and hapyness returned to the heart of man.
Not wanting to be further interrupted, God decided to prender the Cavalum in the caves where still today one can ear his cries of rage and despair.


A toca do cavalum
At machico, in madeira, there are some huge caves where it is said that the cavalum (devil) is in jail. The legend sais that it was the forces of good that emprisioned him there after he tryied to destroy the world with storms. Thruth is that, those who live nearby garante that, during the most stormy nights, it is possible to ear the urros raivosos e desesperados of the cavalum, because he feals emprisioned.

The Furnas do Cavalum are named after a local legend about a devil called Cavalum, who was imprioned in the cave. The lava tube is of great importance and has numerous specialties, and at the moment the process of the creation of a natural reserve is on its way. It is of geologic relevance, as it allows a view on the volcanic history of the now inactive island of Madeira. It is also of biologic importance with several troglobiont living in the cave, including crustaceans, spiders and flies. Fourteen invertebrates live in this tubes, three of them are endemic on Madeira, one of them exists only in this cave. But it is also part of the cultural heritage of the islanders, as numerous legends are told about the cave. And despite the stories about the devil, the cave was used as a refuge by the locals during violent uprises

http://www.showcaves.com/kmz/pt/Cavalum.kmz