In his 1939 article, author Harry E. Wheeler describes another Helicoprion fossil, based on the species H. sierrensis, collected by J. H. Menke, that resides at the University of Nevada, W. M. Keck Earth Science and Mineral Engineering Museum. This fossil is number 1002 and is currently on display in case 62. The mouth consists of a whorl separated into three and a quarter volutions.