Notice of remains of extinct vertebrata, from the Valley of the Niobrara River, collected during the Exploring Expedition of 1857, in Nebraska, under the command of Lieut. G. K. Warren, U. S. Top. Eng., by Dr. F. V. Hayden, Geologist to the Expedition
Published in Proceedings: Academy of Natural Sciences of Philadelphia, in 1858, in volume 1858, pages 20-29
Date published:1858