Victoria Member

Judith River Formation Stratigraphic range: Campanian, 80–75 Ma PreЄ Є O S D C P T J K Pg N ↓
"Leonardo," a rare intact mummified Brachylophosaurus canadensis uncovered in the Judith River Formation.
Type	Geological formation
Unit of	Judith River Group
Sub-units	Birch Lake Member, Ribstone Creek Member, Brosseau Member, Victoria Member
Underlies	Bearpaw Formation
Overlies	Claggett Formation, Pakowki Formation
Thickness	max 360 meters (1,180 ft)
Lithology
Primary	Siltstone and sandstone
Other	Coal, coquinas
Location
Coordinates	47°40′N 109°39′W / 47.667°N 109.650°W / 47.667; -109.650 (Judith River Formation)Coordinates: 47°40′N 109°39′W / 47.667°N 109.650°W / 47.667; -109.650 (Judith River Formation)
Region	Montana
Country	United States
Type section
Named for	Confluence of Judith River and Missouri River
Named by	F.V. Hayden, 1871; F.B. Meek, 1876.

The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the upper Cretaceous, between 80 and 75 million years ago, corresponding to the "Judithian" land vertebrate age. It was laid down during the same time period as portions of the Two Medicine Formation of Montana and the Oldman Formation of Alberta. It is an historically important formation, explored by early American paleontologists such as Edward Drinker Cope, who named several dinosaurs from scrappy remains found here on his 1876 expedition (such as Monoclonius). Modern work has found nearly complete skeletons of the hadrosaurid Brachylophosaurus.

The Judith River Formation is composed of mudstone, siltstone and sandstone.Coal beds, bentonite and coquinas are also observed.

The Judith River Formation conformably overlies the Claggett Formation and Pakowki Formation. It is overlain by the Bearpaw Formation. It is equivalent to the Belly River Formation in the southern Canadian Rockies foothills, the Lea Park Formation in central Alberta and the Wapiti Formation in the northwestern plains.