These trips are custom-designed for the geology enthusiast. I pick an existing trip or develop a new one and propose a time frame for offering that trip such as "September 2015". People contact me to be placed on the interested parties list for that trip. When enough people are interested, I finalize the trip dates and costs and announce the trip to the interested parties list and collect deposits. I then announce the trip to the general public to fill any remaining spaces. No previous geologic course work is required.
Bay Nature video

Bay Nature Magazine Salt Point Geology Hike

International trips


Scotland Geology TripScotland Rocks! Geology Field Trip
June 2-13, 2015 - $4,080/$750 single supplement
Full with 21 (Next Trip June 2017)

Photos from previous Scotland trips

Travel through Northern and Central Scotland studying fundamental geological concepts and exploring the landscapes and geology of the Scottish Highlands in this unique 12-day field trip.  Scotland boasts spectacular scenery and the most varied geological landscapes of any country of its size in the world.  Edinburgh, the capital of Scotland, is one of the most beautiful cities in Europe and has two volcanoes to boot!  The trip includes multiple night stays in Edinburgh, Inverness, Ullapool, and the Isle of Skye.

Day trips will study fundamental concepts that were important in the development of geology as a science.  Participants gain first-hand experience in relative dating principles and interpreting geologic history.  Four days will be spent exploring the area around Edinburgh and will include Edinburgh’s volcanoes, the area around Dunbar, St. Andrews, and Siccar Point, the location of Hutton’s Unconformity.  The next eight days will explore the Scottish Highlands, including a three-night stay on the enchanting Isle of Skye, whiskey-tasting, castles and more!  Trips to the north and northwest will study geological processes, structural geology, and landscape development, expanding on the tools learned in Edinburgh.

Details on the 2015 Scotland Rocks! trip     Itinerary for 2015 Scotland Rocks! trip
Contact Tom for details on Scotland Rocks! 2017 and to be added to the Interested Parties list.


Scotland Geology TripIceland GeoAdventure
July 26–August 9, 2016
Full with 26 (Next Trip August 2017)

An 14-day adventure to one of the world's geologically most fascinating places with Doris Sloan, me, and a fabulous local guide, Elisabet Brand, who knows everyone and seemingly everything Iceland! 

Iceland, the land of "fire and ice" has been called "the ultimate nature experience." In our two weeks in Iceland you will experience a great variety of delights – scenic, geologic, cultural, culinary and historical. Come experience Europe's largest glacier and waterfall, plate tectonics in action, Vikings, geothermal energy and hot springs, horses, Puffins, and great food and folks.

Iceland is one of the world's geologically most fascinating places, where you can experience plate tectonic, volcanic, hydrologic, glacial, and erosional processes firsthand. It is the only place in the world where you can walk across a spreading plate boundary. In Iceland the North American and Eurasian plates are rifting apart and magma forms new crust. Iceland's great variety of volcanoes and volcanic features is due to this spreading plate boundary as well as the presence of a hot spot. The heat from the magma creates Iceland's many hot springs, its geysers and the abundant geothermal energy. In addition, Iceland has Europe's largest ice sheet and largest waterfall, many glaciers, deeply carved fjords, and dynamic ocean shores. The scenery created by these geologic processes is unique and extraordinarily beautiful.

Contact Tom for details on the Iceland GeoAdventure and to be added to the 2017 Interested Parties list.

Photo by Sue Willson - Svinafellsjökull in south Iceland, one of the outlet glaciers from the Vatnajökull ice sheet.

U.S. trips


Yosemite/Eastern Sierra Geology Field TripYosemite/Eastern Sierra Geology Field Trip
September 16-20, 2015 - $500 Just a few slots left

The Yosemite and Eastern Sierra trip is a 5-day exploration of the Yosemite Valley and the Eastern Sierra from Bridgeport to Bishop, including Devil's Postpile, Bodie, Mono Lake, and the Long Valley Caldera.  The beauty and spectacular geology and landscapes of the Yosemite Valley are awe inspiring.  The Mammoth area is the most active volcanic area in the continental U.S. in the last million years and has some impressive glacial features.  We will even have the chance to soak in several hot springs!  Camping and lodging options are planned in both the Yosemite Valley and Mammoth area.
Photos of the Yosemite/Eastern Sierra Geology Field Trip
Photos of the Yosemite/Eastern Sierra Geology Field Trip by Anne Leonard

Details on the Yosemite/Eastern Sierra Geology Field Trip


Grand Canyon Geology TripGeology of Grand Canyon National Park
Upper Grand Canyon: Aug. 29-Sep. 3, 2016
$2,085 Rafting Trip + $715 Williams GeoAdventures Services = $2,800

Upper & Lower Grand Canyon: Aug. 29–Sep. 11, 2016
$3,775 Rafting Trip + $425 Williams GeoAdventures Services = $4,200

Full with 21. Wait List (Next Trip August 26-31, 2017)

Photos from previous Grand Canyon trips

Imagine yourself on a raft on the Colorado River entering into Grand Canyon National Park. This could be you! What better way to raft and explore the Grand Canyon than with a geologist!

This trip includes a 6-day oar-powered rafting trip on the Colorado River into Grand Canyon National Park from Lees Ferry to Phantom Ranch. There is also a travel day before and after the trip.

Join me on an exciting journey back through geologic time. The rafting trip travels through progressively older rocks that span the entire Paleozoic Era as Marble Canyon deepens, before reaching the 1.8 billion year-old rocks of the Inner Gorge of the Grand Canyon. This is one-third of the age of the Earth! The geology trip reading assignments are on John Wesley Powell and his explorations of the Grand Canyon and the geologic history of the Grand Canyon and Colorado Plateau. The field trip focuses on geologic processes at work in the canyon, such as weathering, erosion, and mass wasting; depositional environments and sedimentary structures; geologic time and dating; faulting and folding; and igneous and metamorphic rocks. The trip includes a strenuous hike out of the Grand Canyon from Phantom Ranch to the South Rim and numerous daily side canyon hikes.Details on the Grand Canyon Rafting and Geology Field Trip


CA North Coast Geology TripCalifornia North Coast Geology Field Trip
September 16–18, 2016 - $450 Registration Open

Photos from previous North Coast trips

Explore the remarkable geology along the coast north of San Francisco from Bodega Head to Mendocino in this three-day field trip, spending nights in cliff-top custom homes. Wave-cut platforms, rocky headlands and sea stacks, uplifted terraces, crashing waves, and wide sandy beaches are your outdoor classroom as you discover how the collision of ocean and land has shaped the shore. You explore rocks formed millions of years ago when the ancestral Pacific plate collided with the North American plate, leaving the remarkable and world-famous sequence of marine sedimentary and volcanic rocks called the Franciscan complex. You also investigate the impact of tectonic movements along the San Andreas Fault that are lifting the land and slowly sliding rocks to the west of the fault zone toward Alaska.

The itinerary includes Bodega Head, Mammoth Rock, and Fort Ross on the Sonoma Coast, and Anchor Bay, Bowling Ball Beach, Point Arena, and the Big River on the Mendocino Coast, as well as shorter stops along the way. Participants stay at one or two Irish Beach homes with stunning ocean views of Point Arena. There are numerous short hikes of up to two miles. Details on the California North Coast Geology Field Trip


Death Valley Geology TripGeology of Death Valley National Park
March 11–16, 2017 - $600

Photos from previous Death Valley trips

Come experience the geological playground that is Death Valley National Park in this unique week-long field trip. Travel through geologic time and view the limestones and volcanic rocks of Titus Canyon. Explore a ghost town at Rhyolite. Hike through the colorful sediments of Golden Canyon. Ponder the mystery of Racetrack Playa. Hunt for fossils at a Paleozoic limestone reef.

This geology field trip begins and ends in Bishop, California. We all meet in Bishop on Saturday evening and return the following Friday evening. We stay at a Bishop motel those two nights. We enter into Death Valley from the north on Sunday through Wesgard Pass and return from the south on Friday through the Panamint Valley. We stay in Death Valley for five nights at Furnace Creek. Contact Tom for details on the 2017 Death Valley Geology Field Trip and to be added to the Interested Parties list.



Death Valley Geology TripGeology of Lassen Volcanic National Park
July 2017 - $400

Join me in an extended weekend geologic field study of Lassen Volcanic National Park, the most recently active Cascade volcano in California. Hike to the top of Brokoff Mountain, with views of six physiographic provinces. Explore the inner craters of Cinder Cone, a volcano that has erupted several times in the last few hundred years. Visit the hot springs at Bumpass Hell and Sulphur Works. Hike through a lava tube cave and witness the devastation of a volcanic mudflow from the 1913 eruption of Lassen. Discover how this volcanic region is related to movements of the North American and Pacific tectonic plates. Contact Tom for details on the 2017 Lassen Geology Field Trip and to be added to the Interested Parties list.

Private Half-Day or Full-Day Geology Field Trips
Along the Marin and Sonoma Coast from the Marin Headlands and Point Reyes to Salt Point State Park I would love to design a short trip for your family or group. Price negotiable based on group size.
Contact Tom for details

Past Trips


Italy Geology field tripItaly Rocks! GeoAdventure
June 2014

Photos from the Italy trip

A fabulous 15-day tour of Northern and Southern Italy, exploring up-close the volcanoes and splendid landscapes and geology, in this once in a lifetime experience of Italy's geologic wonders. This tour is packed with amazing hiking adventures, expert guides, wonderful accommodations and food, leisure time, fun – and visit six UNESCO World Heritage Sites!


California North Coast Geology Field Trip
March and September 2014


Eastern Sierra Geology Field Trip
October 2013


Yosemite/Eastern Sierra Geology Field Trip
October 2012


Scotland Rocks! Geology Field Trip
July 2012


Geology of Grand Canyon National Park
June 2011


Geology of Death Valley National Park
April 2011