I am with @rustyshakelford, it is rail dust. Don't panic, I did when I saw it on a new Ram I purchased. I took my Ram back to the dealer and they did a full detail removing the rail dust at no charge.
This is Iron -X and should easily take care of rail dust and iron deposits on your paint.
lots of reviews you can read from user of the product. I have used this to to clean wheels and paint before detailing and it works great, just follow the directions.