This was back when French Canadian immigrants first settled in Rhode Island, and things were hard. Everyone wanted a nice stone church, but the parishioners worked all day at difficult menial jobs. They had almost no free time and very little energy to work on the church.
The priest was discouraged, but determined to get a good church for his flock. He prayed and prayed to God for guidance, until one night the Virgin Mary appeared.
She said, "God has answered your prayer. Outside in the yard you will find a horse. He has the strength of twenty horses, and can work without food and water."
The priest was elated."Thank you Holy Mother..."
The Virgin raised one finger in warning. "But he is no ordinary horse. He will obey your commands, but whatever you do, don't take off the special bridle he wears!" And with that ominous note, the Virgin disappeared in a blinding flash of light.
The priest went outside, and as promised found a horse standing in his yard. The beast was enormous and blacker than night itself. It looked at the priest with angry red eyes, a bridle jammed tightly in its mouth.
The beast's diabolic nature was obvious to the priest. Had God sent the Devil to work for good? But the priest accepted that God works in mysterious ways, so he named the horse Old Nick and led him the next morning to where the church was being built.
"Whatever you do, don't take off his bridle," the priest said as he gave the horse to the foreman. The foreman was a spooked by the gigantic horse, and readily agreed to the priest's command. Things went well for a while. The horse was able to haul heavy stones tirelessly all day and the church went up quickly.
But the longer Old Nick worked on the project, the sicker and more listless the foreman became. Every night he dreamt that Old Nick glowered and spoke, threatening to drag him to Hell. Finally he couldn't take anymore and just lay feverish in bed.
He summoned one of the younger parishioners to his house. "I want you to take over managing the church construction," he moaned. "But whatever you do, don't take the bridle off Old Nick."
"No problem," the young man said. "Don't take off the bridle!" He whistled as he walked back to the construction site, pleased at his promotion.
The young man was not the brightest person in the parish, and didn't understand why everyone was so nervous around Old Nick. It was a hot summer day, and around noon time he went down to the Blackstone River to cool off. He brought Old Nick with him. As the young man splashed around, he felt bad for the horse, who looked hot and uncomfortable.
"Do you want a drink of water, horsey?" he said. "Here, let me take off that bridle so you can drink."
As soon as he took off the bridle the horse gave terrifying neigh that shook the earth. It knocked the man across the river with one hoof, and then leapt across the water in one jump. Old Nick landed on a ledge on the other bank so heavily that the stone split in two, and he disappeared down into the newly formed chasm.
When the priest found out what happened he rushed to the chasm, but it was too late - the demonic horse had made his way back to Hell. He had also opened a gateway to that infernal realm, and for many years the chasm was a source of unholy phenomena. Wagons passing by would lose their wheels, and people walking by at night told of horrific wailing emerging from the cave. Some people even claimed that strange, wolfish beings were seen lurking nearby. These were the loup garous, the Satanic werewolves of French folklore. The priest became disillusioned - how could God let this happen? - and neglected his parish.
Dues to all these strange activity the chasm became known as the Devil's Hole. Things went on this way for many years until a new priest came to Woonsocket. He was astonished that a gateway to Hell was allowed to be open in his parish. Gathering together a group of brave men, he erected a cross at the Devil's Hole and said prayers to God. From that time onward the strange phenomena stopped, and Woonsocket was freed from the black horse's curse.
The Devil's Hole is supposedly located in the Fairmount area of Woonsocket. This guys in this video try to find it, but don't have much luck. I think the video is pretty funny, but has some obscenity so don't watch if you find that type of thing offensive.
I'd be curious to find out when this story was first told. I've seen it in M.E Reilly-McGreen's Rhode Island Legends and in S.E. Schlosser's Spooky New England, but I'm assuming it is older than those books, which were both printed recently. The Catholic themes are interesting and aren't seen in too many New England folk tales. There are many places in New England named after the Devil, and many stories to explain them, but not very many involve the Virgin Mary!
The magic horse who can help build things is an old folk motif, and is found for example in the Norse myth about the gods building Asgard. I mentioned that in an earlier post about the Devil building a barn.
Finally, I'll just say that I love a story where someone is told not to do something. "Don't use this key!" "Don't go in the basement!" "Don't stay out past midnight!" You just always know the warning will be ignored at some point.