Tynsky's Fossils History


Sylvester "Switz" Tynsky | 1960

In the 1960's, Sylvester "Switz" Tynsky and his two sons, Robert D (Bob) and James A (Jim A), opened the very first of the nearshore sandwich bed quarries. It was located on a 40,000-acre sheep ranch belonging to a friend of Bob's, Ronald Thompson. At first, other quarries were skeptical about whether the Tynskys would find many fossils at this location because it was so far north of where the historic FBM quarries were. Development of the quarrying operations started slowly, but fossils were found!


James "Jim A." Tynsky | 1970

In the mid-1970's, Bob and Jim A. split the Tynsky operation between them. One part for Jim A. and his son Duane, and the other part for Bob, his son James (Jim E.), and Jim E's wife Karen. They were soon joined by their children, Robbie and Stacey, adding a fourth generation of fossil diggers to the family.

James "Jim E." Tynsky | 1984

In 1984, Jim E. moved from the FBM Locality H, to the mid-lake, 18-inch layer site on the Lewis family ranch, FBM Locality A, where he leased several acres. Since then, many Field Museum crews come each year building the world's greatest collection of FBM fossils at the Field Museum.

Jim E.'s overall contributions to the scientific and educational development of the FBM have been signficant, but are of the sort that history often does not acknowledge or fully understand.

Rob Tynsky

Robert (Robbie) Tynsky | 2019

Rob grew up on the quarry since he could walk; it was like his second home. As he got older, he was at the fossil shop everyday after school helping his mom and dad. He learned how to prepare fossils at a very young age.

“ I’m very excited to buy this business and continue the hard work of fossil life like my father Jim. With all the luck and hard work, I hope our son, Bryson James,will continue the Tynsky tradition as well." ~Rob

Tynsky's Fossils Team Members

Fossil Lake Story


Fifty-million years ago, ancient Fossil Lake existed in what is now southwest Wyoming. Of its estimated maximum extent of 930 square miles, approximately 500 square miles of sediments remain. The 230 square miles across the center of the ancient lake-bed contain exceptionally fossiliferous sediments and associated geologic features including deltas, beaches, springs, and rocks from the center and near shore environments.

The unusual chemistry of Fossil Lake prevented decay and scavenging of dead organisms, while millimeter-thick layers of alternating limestone and organic matter slowly accumulated. The resulting laminated limestone contain the highest concentration of articulated fossil fish in the world. These fish, other fossilized aquatic organisms, and associated geologic features, make Fossil Lake the world's best Paleogene record of a freshwater lake ecosystem.

Since its discovery int he 1870's, more than a million perfectly preserved fossil fish have been recovered. Preserved with the fish in the laminated limestone is a complete ancient aquatic ecosystem; cyanobacteria, plants, insects, crustaceans (shrimp, crayfish, and ostracods), amphibians (frog and primitive salamander), alligators, turtles, birds, and mammals, including the oldest pantolestid (otter-like animal). The subtropical terrestrial ecosystem surrounding the lake is also represented by rare fossils, including a horse, two snakes, lizards, two bat species, birds, an apatemyid (an arboreal insectivore), a miacid (primitive carnivore), insects, and more than 325 types of leaves, seeds, and flowers.