Welcome to Williams GeoAdventures! I pride myself in custom-designing GeoAdventures for folks who love geology, but we do so much more. By partnering with top-notch expert local guides, each trip combines not only fabulous geology and the beauty of the natural world, but offers experiences in each regions historic, cultural, and gastronomic delights. And we always have a lot of fun!

Bay Nature video

Bay Nature Magazine Salt Point Geology Hike

These trips are made 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 2017". People contact me to be placed on the interested parties list for that trip. People on the list have the first opportunity to sign up for the 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.

International trips


Scotland Rocks! II – The Islands of the West Geology Field Trip
June 6-17, 2016 - Registration Open (only two spaces left)

Scotland Geology Trip

Photos from previous Scotland trips

Join Tom Williams and Scottish geology guide Angus Miller for this exclusive tour of some of Scotland's less visited western islands, and some fabulous geology and scenery. This 12-day field trip will take us from Glasgow, Scotland's largest city, to the quieter reaches of the Inner Hebrides, interacting with the small communities that call these remote islands home.

We'll visit the picturesque island of Arran, exploring an intersection of several different geological periods and one of James Hutton's unconformities. We'll travel through the metamorphic Highland rocks, and get a glimpse of deep time exploring ice-age sedimentary rocks that are about 600 million years old in the Garvellach islands. Extraction of slate from the islands of Easdale and Luing provided roofing material for Scotland and further afield, and left behind a stark landscape of some beauty. We'll travel across the island of Mull to enjoy the varied geology of the islands of Iona and Staffa, with its world famous columns of volcanic basalt.

Travelling further north, our final stop will be on the small islands of Eigg and Rum, just south of Skye, where a combination of sedimentary and volcanic rock has left a legacy of geological and scenic diversity, which has influenced the settlement and human story. The trip will culminate with a scenic rail journey across the Highlands and back to Glasgow and onwards to London.

Details on the Scotland Rocks! II trip 


Dolo-Slovo GeologyDolo-Slovo Rocks! Geology Field Trip
June 21-30, 2016 - Registration Open

The Dolo-Slovo Rocks! Trip visits three of the most amazing regions of North-eastern Italy and Slovenia: The Julian Alps Lake Bled and the Škocjan Caves of Slovenia, the Trieste/Carso (Karst) area, and the enchanting Dolomite Mountains.

Julian Alps - The Julian Alps are renowned for their scenic beauty, Slovenian culture, and gastronomic specialties.  We will also visit the World Heritage Site at the unforgettable Škocjan Caves in Slovenia.

Trieste and Carso area - Trieste has the beauty of the azure Adriatic Sea.  In this corner of Italy is the classical beauty of the Mediterranean landscape, tempered by the first hints of the Slavonic worlds, as well as the Alps, which provide an almost magical backdrop to the area.  The long-standing Austrian-Hungarian presence can still be felt in the air here, and has left many traces in the landscape, in the cuisine, and in the local customs.
The Carso is in fact one cultural and geographical entity, even though it now belongs to two different countries. It is a region known far and wide for its geological features – so important that they even gave their name to a whole series of geological phenomena (defined precisely as 'karstic').

Dolomite Mountains – The Dolomites capture the imagination for their stunning peaks seemingly coming out of the dark green of spruce forests.  The name 'Dolomites', almost speaks for itself as a synonym for "magical mountains", with remarkable geology, charming towns, and delectable fresh local food and wine, handpicked by out fabulous local guide Maximiliano Calligola.  The Dolomite Mountains are a UNESCO World Heritage Site.  We will experience many of the serial properties of the Dolomite World Heritage Site during our stay, including Tre Cime and Bletterbach gorge. 

The trip will include a series of highlights from all three regions. The majestic peaks of the Dolomites – with the immense views they offer, and the incredible experience of walking on what was once the bed of an ocean, will be complemented by the monumental caves we will see in the Carso and Slovenia. We will walk on historical trails, taking in the grandeur of nature as well as the cultural, artistic, historical and gastronomical plenty that these regions offer.   We are talking some memorable meals, folks – and did we mention the wines?

Details on the Dolo-Slovo Rocks! trip
Contact Tom for more information.


Scotland Geology TripIceland GeoAdventure
July 26–August 9, 2016
Full with 26. Wait List (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.


Scotland Geology TripScotland Rocks! Geology Field 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.

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


New Zealand Geology Field Trip
January 2018

Contact Tom for details on the New Zealand Geology Field Trip and to be added to the Interested Parties list

U.S. trips


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 2016 Grand Canyon Rafting and Geology Field Trip

Contact Tom to be added to the 2017 Interested Parties list


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.


Colorado Plateau Geology Field Trip
September 2017

Contact Tom for details on the Colorado Plateau 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

Yosemite-Eastern Sierra Geology Field Trip September 2015

Scotland Rocks! Geology Field Trip June 2015

Italy Rocks! GeoAdventure June 2014 | Photos

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