Students at The Bement School in Deerfield on Friday view examples of Jurassic armored mud balls, a rare geological formation that geologist and Greenfield Community College Professor Emeritus Richard Little, pictured at left, is advocating to make the state’s “official sedimentary structure.” CONTRIBUTED PHOTO/MATT PLAGER

Students at The Bement School in Deerfield on Friday view examples of Jurassic armored mud balls, a rare geological formation that geologist and Greenfield Community College Professor Emeritus Richard Little, pictured at right, is advocating to make the state’s “official sedimentary structure.” CONTRIBUTED PHOTO/MATT PLAGER

Geologist and Greenfield Community College Professor Emeritus Richard Little tells students at The Bement School in Deerfield on Friday about Jurassic armored mud balls, a rare geological formation that he is advocating to make the state’s “official sedimentary structure.” CONTRIBUTED PHOTO/MATT PLAGER

Geologist and Greenfield Community College Professor Emeritus Richard Little tells students at The Bement School in Deerfield on Friday about Jurassic armored mud balls, a rare geological formation that he is advocating to make the state’s “official sedimentary structure.” CONTRIBUTED PHOTO/MATT PLAGER

From left, Camille and Jessie, students at The Bement School in Deerfield, view examples of Jurassic armored mud balls, a rare geological formation. CONTRIBUTED PHOTO/MATT PLAGER