I fished a crystal clear stream filled with boulders or what they call pocket water. I took them all on an #18 black caddis that I tie with black duck quill wings. There was a pale evening dun mayfly hatch later, but no takers on them.
Been there done that scruff. Used to live 10 miles south of the NH line in Mass. I absolutely love those boulder strewn streams up there. Some of those have solid granite bottoms too!
Maine had some awesome streams too.
