BELLY RIVER BEDS 



377 



Cross-bedding is less frequent and sedimentation took place under 

 quieter and more uniform conditions than in the Judith Eiver Beds. 



Only two or three local beds of lignite of inferior quality appear in 

 the upper part of these beds on the Eed Deer River and vegetal remains 

 are less common than in the Edmonton. 



Fossil remains are more abundant than in any of the Cretaceous for- 

 mations and the dinosaurs are more varied in genera and species than in 

 earlier or later formations. The dinosaurs are distinctly more primitive 

 than those of the Lance, but there is no change in facies. This is con- 

 clusively demonstrated in those families adequately known from both 

 formations, such as Deinodontidfe, Ceratopsidae, Trachodontidae, and 

 Ankylosauridae. 



While there is a marked contrast between different genera that do not 

 run through, several in the Lance are clearly derivable from Belly River 

 genera through intermediate forms in the Edmonton. 



In the Deinodontidoe Deinodon of the Belly River, Alhertosaurus of 

 the Edmonton, and Tyrannosaurus of the Lance form a phylogenetic 

 series. 



In the Ceratopsidse the phyla are not so clear, but it seems probable 

 that Triceratops of the Lance was derived from Ceratops of the Belly 

 River through a known but not yet described genus of the Edmonton. 



The Trachodontid^ may now be divided into two groups which share 

 in common a ducklike bill. 



In the first group the skull is without ornamentation, pelvis with 

 ischium terminating in a blunt rounded point. Tracliodon, typical of 

 this group, ranges through the Belly River, Edmonton, and Lance. 

 Closely related to it is the genus Kiitosaurus, which is known only from 

 the Belly River Beds and the Ojo Alamo Beds. 



In the second group the skull is ornamented by a crest; pelvis with 

 ischium terminating in a large footlike end. This group is not known to 

 occur in the Lance, but three genera are now known from lower horizons. 



Hypacrosaurvs occurs in the Edmonton; also in the Belly River. 

 Saurolophus occurs in the Edmonton, and a closely related genus not yet 

 described is at present known only from the Belly River. 



In the Ankylosauridae the genus Ankylosaurus passes through the Belly 

 River, the Edmonton, and the Lance. A closely related genus not yet 

 described occurs in the Belly River and the Edmonton, but is not known 

 from the Lance. 



In the Ornithomimidge Ornithomimus passes directly through the 

 Belly River, Edmonton, and Lance. 



The invertebrates and plants are determined unquestionably of Judith 



