NEW VERTEBRATE TRACKWAYS FROM THE HELL CREEK (LATE MAASTRICHTIAN) OF SOUTHWESTERN NORTH DAKOTA

Recent discoveries of two new vertebrate trackways from the Hell Creek Formation of North Dakota are attributed to an undescribed shore bird and a crocodilian. The avian trackways are four in-filled anisodactyl tracks in epi-relief in sandstone, with prominent hallux imprints. Traces of under toe scales are visible on one track. These tracks are associated with ripple marks, inferring a nearshore lacustrine environment. A partial crocodilian trackway is represented by four distinct foot prints in epi-relief in ironstone (siderite) and show both left pes and right manus imprints. These tracks represent new occurrences within Avian and Crocodilian ichnospecies as well as new occurrences in the Hell Creek Formation of south western North Dakota.