Alonzo Hancock and Miomastodon Jaw

This photograph was taken by Oregon Journal photographer Edmund Lee in March 1953. It shows Alonzo Hancock with the jawbone of a miomastodon that he excavated in 1941. Miomastadons were relatives of the modern elephant that lived in Oregon during the Miocene Epoch—around 25 to 5 million years ago.

Alonzo Wesley Hancock (1884-1961) worked for thirty-five years as a postman in Portland, but he is best known for his contribution to the science of paleontology. In the early 1930s, Hancock, known to his friends as Lon, began combing the hills of the John Day country in search of fossils. By the 1950s he had amassed a collection of more than 10,000 plant and animal specimens, which he kept in his Portland home. He made his collection available to scholars, many of whom based their work on Hancock’s finds, and he also opened his home museum to school children, thousands of whom learned about Oregon’s geologic history from Hancock.

Hancock is best known for being the first to find animal fossils in the Clarno Formation, located about eighteen miles west of Fossil. The lack of vertebrate fossils in this site puzzled researchers for decades. There was abundant evidence of plant life, but no vertebrate fossils were found until Hancock discovered a fossilized rhinoceros tooth in September 1942. Viola Oberson, one of the founders of the Oregon Museum of Science and Industry (OMSI), notes that “this discovery of a Clarno Hyrachyus or rhinoceros tooth dated the Clarno Formation as middle Eocene [around 49 to 37 million years ago] and led to the discovery of the mammal beds.”

Hancock excavated the miomastodon jaw shown above in 1941. He and University of California paleobotanist Chester Arnold were hunting for fossils around Ironside, located in Malheur County, when they discovered the 450-pound upper jaw and skull of a miomastodon. It was the best specimen of a miomastodon that had ever been discovered, though it lacked the lower jaw. Twelve years later, however, Hancock returned to Ironside and managed to find the missing lower jaw.

After his retirement from the U.S. Post Office, Hancock and his wife Berrie established a permanent camp near Clarno where they taught classes on geology and paleontology to school children during the summer. The camp, known today as the Hancock Field Station, is currently operated by OMSI, which continues Hancock’s educational legacy by offering summer programs in geology and ecology. Hancock, who died in 1961, willed his impressive collection of fossils to OMSI.

Further Reading:
Bishop, Ellen Morris. In Search of Ancient Oregon: A Geological and Natural History. Portland, Oreg., 2003.

Oberson, Viola L. “Alonzo Wesley ‘Lon’ Hancock (1884-1961): A Profile.” Oregon Geology 41, 1979: 187-191.

Orr, Elizabeth L., and William N. Orr. Oregon Fossils. Dubuque, Iowa, 1999.

Written by Cain Allen, © Oregon Historical Society, 2005.