You are looking for a round black tin about the size of an Altoids container. Depending on the time of year, special tools or equipment to retrieve the cache may be necessary. Please ensure the log and pencil are sealed well inside the plastic bag. Muggles can be nearby, especially in summer, so use stealth when retrieving and replacing!
Hint will be added if it becomes necessary, or message me if you are having seroius trouble. :)