524 THE POPULAR SCIENCE MONTHLY. 



mist, since, although reptilian in all their main characters, they show 

 clear affinities with the birds, and have some features which may point 

 to mammals. The Cretaceous Dinosaurs were all of large size, and 

 most of them walked on the hind-feet alone, like modern struthious 

 birds. Two well-marked types may be distinguished among the re- 

 mains discovered in deposits of this age: the herbivorous forms, 

 represented mainly by JIadrosaunis, a near ally of the Iguanodon of 

 Europe ; and their carnivorous enemies, of which Bryptosaurus 

 (Lcelaps) may be considered typical in this country, and Megalosau- 

 rus in Europe. Near the base of our Cretaceous formation, in beds 

 which I regard as the equivalent of the European Wealden, the 

 most gigantic forms of this order yet discovered have recently been 

 brought to light. One of these monsters (Titanosaurus montanus), 1 

 from Colorado, is by far the largest land-animal yet discovered ; its 

 dimensions being greater than was supposed possible in an animal 

 that lived and moved upon the land. It was some fifty or sixty feet 

 in length, and, when erect, at least thirty feet in height ! It doubt- 

 less fed upon the foliage of the mountain forests, portions of which 

 are preserved with its remains. "With Titanosaurus, the bones of 

 smaller Dinosaurs, one ( Nanosaums), not larger than a cat, as well as 

 those of crocodiles and turtles, are not uncommon. 3 The recent dis- 

 covery of these interesting remains, many and various, in strata that 

 had long been pronounced by professional explorers barren of verte- 

 brate fossils, should teach caution to those who decline to accept the 

 imperfection of our knowledge to-day as a fair plea for the supposed 

 absence of intermediate forms. 



In the marine Cretaceous beds of the West, only a single Dinosaur 

 (LTadrosaurus agilis) has been found, but in the higher fresh-water 

 beds, which mark the close of this formation, their remains are numer- 

 ous, and indicate several well-marked species if not genera. In the 

 marine beds on the Atlantic coast, the bones of Dinosaurs are fre- 

 quently met with, and in the Upper Cretaceous Greensand of New Jer- 

 sey, the type specimens of Hadrosaurus and Dryptosaurus were found. 

 In Cretaceous fresh-water deposits on the coast of Brazil, remains of 

 this order occur, but the specimens hitherto discovered are not suffi- 

 ciently characteristic for accurate determination. This is unfortu- 

 nately true of many Dinosaurian fossils from North America, but the 

 great number of these reptiles which lived here during the Cretaceous 

 Period promises many future discoveries, and substantial additions to 

 our present knowledge of the group. 



1 This generic name proved to be preoccupied, and I have substituted for it, Atlanto- 

 saurus. 0. C. M. 



2 A new order of huge reptiles (Slegosauria), apparently allied to the Dinosaurs and 

 Chelonia, and two new genera of Dinosaurs (Apatosanrus and AUosaums), have since 

 been described by the writer from the same Upper Jurassic horizon. (American Journal 

 of Science, December, 187Y.) 



