In this instance Samson is the saint, or to be more precise Bishop Samson of Dol (485-565). His name has been appended to a lot of stones, the reason why is not known but there are a few in Pembrokeshire, Carreg Samson perhaps being the most famous. Though the answer here may be that the small island just in front of this cromlech accounts for his presence as there is also the Grave of St.Samson's Finger; one of the stories is that he threw the stones from the island to the mainland. There is also another small cromlech Carnwynda which has his name attached.
Therefore at Longhouse Farm we have Carreg Samson;
Trelly's cromlech in St.Nicholas is Ffyst Samson (Samson's flail)
At Nevern there is Bedd Samson (Samson's Grave).
At Llanfyrnach a great stone said to have been thrown the summit of Freni Fawr in the Prescilies.
Two other cromlechs, one already mentioned at Garn Wynda, the other at Garn Wen
Information taken from Myths and Legends of Wales retold by Tony Roberts
Turning to Breverton, a fuller history reveals that this saint is supposed to have incised a cross on a pagan stone in the district of Tricurius in Cornwall. Three stones in Glamorgan named after him, and there a couple at Dol in Brittany.
Interestingly, there is a tiny (ruined) Chapel at Merythr Mawr set within an Iron age hill fort with two early christian burial stones inside the chapel. One was called the 'Goblin Stone', the story being that a goblin would grab the hands and feet of passers-by and force them through the four holes of the celtic cross.
In the written record his uncle is supposed to be the famous King Arthur (Arthwys ap Meurig)and that his cousin Morgan became king of Glamorgan.
Garn Wynda/Carreg Samson
This particular type of cromlech is known as a sub-megalithic, because the capstone rests on the ground, sub megalithic cromlechs are a particular feature of this area of Pembrokeshire. Though it looks easy to find, this particular one was difficult, they are hidden in the jumble of rocks similar to the ones at Carn Llidi on St.David's Head.
Also managed to jam the lock of the car here, and stood outside the car with my dog panicking on this lonely Welsh lane, eventually drew my wits together and managed to gently unlock it. The car was not happy this time in Wales, and kept heating up with steam gently billowing out of the bonnet. As I had been told it did not need water, was somewhat perplexed where to put it..but travelling out of Haverfordwest back home, it did it again, pulling into a layby and slowly coming to a stop. A police car pulled up behind me, and as the nicest person in the world at that time he identified my problem and went over the road to a golf course and brought back water for me, admonishing me to drive carefully and stop and fill up at garages along the way!