HALLOPUS, BAPTANODON, ATLANTOSAURUS BEDS 349 



Because of certain incorrect statements which have been published 

 recently concerning the discovery of the vertebrate fossils of the 

 Atlantosaurus beds, it will be worth while to give briefly the real 

 history. Probably the first specimen of a vertebrate critically studied 

 by a paleontologist from these beds was that described by Leidy in 

 1873 in his Contributions to the Extinct Vertebrate Fauna of the 

 Western Territories, as Poiciloplenron valens, and named Antrodemus 

 generically in his plate — a genus apparently identical with that 

 afterwards called Labrosaurus by Marsh. This specimen was 

 obtained by Hayden in Middle Park, Colo., where similar specimens 

 were reported to be common. Prior to this time Marsh had observed 

 dinosaur bones at the extreme western end of Lake Como, Wyo., 

 in 1868, but had not appreciated the value of his discovery, nor 

 published anything concerning the fossils. The history of the dis- 

 coveries later may be given as published by me in the Transactions 

 of the Kansas Academy of Science for 1878, as follows. I have 

 substituted only the name of Mr. Beckwith for that of Mr. 

 Berthoud, both of whom had been associated with Mr. Lakes in his 

 investigations. 



To an English geologist, Professor Arthur Lakes, of Golden, Colo., credit 

 is due for first detecting the osseous character and appreciating the scientific value 

 of the fossils. While engaged one day in March, 1877, in company with Captain 

 H. E. Beckwith, in collecting Dakota leaves from the summit of the ridge or 

 "hog-back" near Morrison, he discovered a huge caudal vertebra in bas-relief 

 upon a slab of sandstone. Upon further investigation, a large quantity of bones 

 was collected and shipped to Professor Marsh, of Yale College, by whom they 

 were described under the name of Titanosaurus montanus. Almost contem- 

 poraneously with this discovery the fossils were made known at Canon City 

 by Mr. O. Lucas, a school-teacher, and by Mr. William Reed, an intelligent section 

 foreman of the Union Pacific Railway. Specimens from the former locality 

 were sent to Professor Cope, of Philadelphia, by whom they were named Camera- 

 saurus supremus. Since then numerous other localities have become known in 

 Colorado and Wyoming, and I doubt not that future explorations will bring 

 to light scores of outcrops rich in these vertebrate fossils. 



In June or July, 1877, Professor B. F. Mudge, of Kansas, was 

 sent to Morrison by Professor Marsh to exploit, in connection with 

 Professor Lakes, the fossils of that region. From there Mudge went 

 shortly to assist Mr. M. P. Felch in opening the famous Marsh quarry 



