Hello Sylvia,
Yes I am aware of the excavations at L'Anse aux Meadows in America. I have found the reference to the inscription i was talking about.
It is known as the "Kensington Stone" and was "found" in Minnesota around 1900, there has been a lot of shcolarly argument about its authenticity but the opinion among experts is that it was concocted by the "finder". There is apparently a museum dedicated to it in Minnesota where they will give you carefully drafted evasive answers to your questions.
The account that I read is in a book called simply "Vikings" by the late Magnus Magnusson published in 1980.
Rick