There are many areas that do not require special permission, but there are also many protected ones and you will need a permit. Always bring lots of water, sun block and bug spray when working in the summer. If you are on a north shore beach, you want to look for evidence of glacial activity. Striations are parallel scratches etched into a rock's surface by glacial transport. Chattermarks appear as half moons dug into a rock.
Erratic boulders are boulders that differ in mineral composition from the native bedrock of an area.
These boulders can be as large as a house and were brought to the area by a glacier. Unless you have a landmark, it may be difficult and often impossible to find the exact spot you were previously working at. The important thing is to choose a mark that is not going to move for a number of years. A good choice would be a large boulder, building or other semi-permanent feature. I chose a large erratic on the beach that was situated close to my research spot.