210 TEN YEAES' PROGRESS IX VERTEBRATE PALEONTOLOGY 



be youngest Lower Cretaceous in age. Here a remarkable deposit of 

 sauropods has been found, the work of collecting now being conducted by 

 Janensch for the Berlin Museum. The most striking species is Giganto- 

 saurus rohustus, apparently of enormous size, with a humerus 2.10 meters 

 long, ribs 2.50 meters, and a cervical 1.20 meters — bones which seem to 

 show ^^nearly double dimensions in comparison with Diplodocus." The 

 estimated length of this animal is 35 meters, or nearly 114 feet! The 

 Berlin expedition, which began in 1910, is to be continued through the 

 summer of 1912, and promises most interesting results. Two other 

 types are mentioned, represented by stegosaur-like dorsal spines, the long- 

 est a meter in length, and fragments of bone apparently belonging to 

 small iguanodonts. Personally I am skeptical on other grounds of the 

 reference of material from the southern hemisphere to the suborder 

 Orthopoda. 



Orthopoda (Predentata) 



orxithopoda, iguaxodontia 



These plant-feeding dinosaurs fall naturally into three groups — nn- 

 armored, armored, and horned — all of which surviTe into the Cretaceous 

 period. 



Of these the unarmored Iguanodontia are the most generalized and 

 their evolutionary history the best known. Like the carnivores, they 

 are also divided into a greater and a lesser group. Of the latter during 

 Cretaceous times we know but little, though Brown report-, having 

 found- one small plant-feeding dinosaur in the Hell Creek beds, the form 

 being as yet undescribed. 



Oi the Trachodontidse much has been learned since the mounting of 

 the first individual at the Yale Museum under the direction of Professor 

 Beecher, in 1901. Following this, two fine specimens were mounted in 

 the American Museum, one in standing and the other in feeding posture. 

 The latter was one of the principal specimens of the Cope collection 

 purchased by the American Museum in 1899, and was found by Wort- 

 man near the Black Hills of South Dakota in 1882. The erect specimen 

 collected by Brown is from Crooked Creek, in central Montana, while 

 that of Yale is from the classic Converse County locality, and was col- 

 lected by Hatcher in 1902. Still a fourth individual, a companion to 

 the Yale specimen, is mounted in the National Museum. Impressions 

 of the skin of this animal were already known from material in Wash- 

 ington and from the fragment of a tail collected by Brown. It re- 

 mained for the veteran collector, Charles H. Sternberg, however, in 1908. 

 to bring to light in Converse County, by aid of his two sons, the most 

 marvelously preserved dinosaur known to science, which seems to have 



