526 GEOLOGY OF THE DEXVEE BASIN. 



In the Cretaceous period that followed, the huge flying reptiles and the 

 gigantic marine saurians, many of them veritable sea serpents in form and 

 habit, clearly prove that the tropical climate still continued in this region. 

 That it prevailed later during this age, the gigantic Ceratopsidse and their 

 many reptilian contemporaries demonstrate by the abundance of their 

 remains deposited in this region, and especially farther north. Their sudden 

 extinction, which left no survivors, is equal proof of a great change in 

 climate, if not of important geological convulsions, at the close of the epoch 

 in which they lived. 



Throughout Tertiary time, as indicated by the rich and varied mamma- 

 lian life, a warm, tempi-rate climate prevailed in the Denver region, and this 

 continued with various changes and a gradually declining temperature until 

 the approach of the Glacial period began to affect all land vertebrate life. 

 The survivors of that epoch and their descendants constitute the existing 

 fauna of to-day 



LIST OF VERTEBRATE FOSSILS. 



The following is a list of the more important vertebrate fossils, espe- 

 cially types known to the writer, which are characteristic of Mesozoic or 

 Tertiary horizons representee! in the Denver Basin, and have been found 

 within or near that area. Some of the more important localities are also 

 indicated. The original descriptions of the types described by the writer 

 will be found in the American Journal of Science. 



ITallopus beds: Near Canyon, Colo. 



Hallopua victor. Nanosaurus agilis. 



Nanosaurus rex. 



Atlantosaurus beds: Near Morrison and Canyon, Colo. 



Atlantosaurus (Titanosaurus) montanus. 1 Stegosaurus Btenops.' 



Atlantosaurus inimanis. 1 Camptosaurus medius. 



Apatosanrusajax.' Laosaurus gracilis. 



Apatosaurua latioollis. 1 Ulosaurua fragilis. 



Brontosaurus excelsus. 1 Labrosaurus f'erox. 



Diplodocua longus. 1 Ceratosaurus nasicornia. 



Diplodocus lacuatris. 1 Diplosaurua 1'elix. 1 



Moroaaurua grandia. 1 Glyptopa ornatus. 



Moroaaurua agilis. 1 Ceratodua Giintberi. 



Stegoaanrus annatua. 1 Dryole8tes graoilia, 



'These forms were found near Morrison ; the others are from near Canyon, but quite a number 

 are common to both regions. 



