Revisiting the Geology of the Fells– Self-Guided Hikes Now Available

Back in December of 2020, guest blogger and board member Steven Engel highlighted the work of Prof. Jack Ridge, a geologist in the Earth and Ocean Sciences Department at Tufts University.  Since 2007, Prof. Ridge has focused a large portion of his research on the geology of the Fells, and made much of his findings available for the public to view at his website, “The Geology of the Middlesex Fells.”

Prof. Ridge has recently updated his website to include a series of self-guided geology hikes throughout the Fells.  He explains:

The compilation of self-guided geologic hikes in the Fells is an outgrowth of my interest in informing the public about the exciting field of geology. The geologic hikes in the Fells introduce the fundamental geology of the Fells along with some of their details. They are an excellent way to introduce natural science. I am especially interested in informing middle through high school students and their teachers about local geology, but anyone can learn Fells geology. Really curious younger students may also find the geology of the Fells interesting. I have also been struck by the curiosity that many hikers in the Fells exhibited, when they saw me in the field.

There are currently five self-guided geology hikes available on the site, all in pdf format, and some in multiple parts:

  • The Skyline Trail (in a 7 part series) – west of Rt. 93

  • The Rock Circuit Trail (in 3 parts) – east of Woodland Road and across southeast Fells

  • The Crystal Spring Trail – north of Pond Street to Whip Hill

  • Virginia Wood – south of Pond Street in Virginia Wood

  • Lawrence Woods – loop from Medford High School

Per Prof. Ridge:

At the beginning of each download document (PDF format) is useful information about what to expect while hiking in the Fells and also some fundamental geology to get started. Each hike route is on DCR trails and they are marked on geologic maps in the guides. Take advantage of the special geologic explanations linked below.

To download these hikes, and to explore the additional geology resources and references produced by Prof. Ridge to expand on the topics discussed in the hike documents, visit the hikes homepage:

Prof. Ridge welcomes questions on these hikes, or feedback on ways to make them more clear and accessible.  He can be reached at

As I slip into the woods on the Virginia Wood Trail the sound of morning traffic on Pond Street quickly fades away. The quiet forest envelops me with rustling leaves and birds calling. I’ve adopted this trail through the Friends Adopt-a-Trail program, but in some ways I feel like it’s adopted me. The lure of the forest is hard to resist, and these early morning forays before work stay with me all day. Of course there’s lots to do, branches to trim back, logs to cut, trash to pick up, but the work is light and fun, and it’s rewarding to help keep the trail clear for others to enjoy. And there’s lots to enjoy in Virginia Wood, between the waterfall at the dam, and all the interesting stories at each station of the Spot Pond Brook Historic Trail.

Mapleleaf Viburnum

Mapleleaf Viburnum

Along the way I notice the changing of the seasons, Indian cucumber leaves turning crimson (photo at top), yellow zigzag goldenrods, and the purple berries of the mapleleaf viburnum. The air is brisk and moist along Spot Pond Brook, the water spilling over a log making a quiet gurgling sound joined by the murmer of crickets, and soft buzzing of bumblebees, working their way through blue asters. Winter brings the first crunch of snow underfoot, white edging on the cracks in rock outcrops, and clear thin ice along the edges of the brook.

Heartleaf Aster

Heartleaf Aster

Some animal sightings are common, like frogs and snakes, while others are more fleeting. One morning I saw a flock of birds noisily chase a red-tail hawk up and down the brook, flying right overhead. Another time a mink slunk right by me running up a tree trunk to quickly cross a jumbled rock talus slope. Deer tracks in the mud of a vernal pool attested to where they ate the tops off of one of their favorite foods, the orange-flowered jewelweed.
It’s always hard to leave the forest and get back into my car to finish the morning commute to work, but I do so with a sense of satisfaction at the work accomplished, and with a serenity that will carry me through the day. I’m often reminded of where I was by finding a leaf in my hair, or burs on my clothes, which always brings a smile to my face. Over time these early morning walks have brought a deeper appreciation of the gift to us all that the Tudor family made in honor of their daughter Virginia.