Top--Conodonts (minute tooth to jaw-like structures, unrelated to modern jaws, that served as a unique food-gathering apparatus in an extinct lamprey eel-like animal) from an upper Ordovician section of the upper Ordovician to lower Silurian Hanson Creek Formation, Eureka County, Nevada, a number of miles west of the western border of White Pine County, Nevada. Specimens: 1-6--Oulodus ulrichi; 7-12--Plectodina tenuis; 13-16, 18-19--Oulodus rohneri; 17--undetermined conodont element (new species, perhaps). Photograph courtesy Walter C. Sweet; I edited and processed the image through photoshop.

Bottom--Conodonts from an upper Ordovician section of the upper Ordovician to lower Silurian Hanson Creek Formation, Eureka County, Nevada, a number of miles west of the western border of White Pine County, Nevada. All specimens referred to genus-species Amorphognathus ordovicucus. Photographs courtesy Michael C. Sweet; I edited and processed the images through photoshop.