Stonehenge

How can we be working in the shadow of a man who's work is generally seen as unreliable? Geoffrey was a man known for his History of the Kings of Britain, as well as his documentation of the prophecies supposedly uttered to Merlin, translated from an unknown language. He appeared to have been drawing upon nationwide myths in his chronicling of the Ancient Kings, He wrote that Merlin was the one to bring the stones to Stonehenge; but how can a mythological character carry stones from Wales to Stonehenge, being a myth? He wrote a story, not an accurate timeline, and thus Stonehenge archaeologists should not be seen as working in the shadow of this fiction writer.