Any introduction to Dogtown must first be qualified with a warning: If you’ve never ridden there before, go with someone who has or take a compass. Otherwise you risk getting lost in this confusing maze of old carriage roads and technical singletrack that got its name from the stray dogs that roamed these thick woods during the early eighteenth century. Before those dog days, locals had tried farming the land. But the rock-strewn landscape wasn’t particularly fertile, and most of the townsfolk moved to the nearby coastline. Thankfully, what was bad for agriculture then is good for mountain biking today. All those rocks make Dogtown a challenging cross-country test for even the best bike handler. You have to ride some sections over and over before figuring out how to clean them. Riding over rocks, granite to be precise, is a hallmark of Massachusetts mountain biking. At the nearby Essex County Greenbelt, locals have crafted a North Shore style trail dubbed Bruce and Tom’s that is a winding, 15-mile series of giant boulders, skinnys, bridges, jumps and occasionally dirt. Back in Dogtown, the biggest boulders serve as landmarks, replacing the trail markers that always seem to be torn down. The north sector has a collection of giant rocks known as Whale’s Jaw. In the southeast you’ll find the Babson Boulder Trail, a combination of technical singletrack and inspirational sayings carved into giant stones. The messages come courtesy of philanthropist Roger Babson, who bought the deserted land in the 1830s, then hired out-of-work stonecutters to engrave the biggest boulders with slogans such as “Get a Job,” “Help Mother” and “Courage.”