564 POPULAR SCIENCE MONTHLY. 



like tail, smooth, scaleless skin, very effective, dolphin-like paddles, 

 and long, pointed snout. Dr. Merriam at first regarded Shastosawus 

 as a segregated or isolated type which developed from some more primi- 

 tive ichthyosaur stock in this ancient bay of the Pacific; but his more 

 thorough study and the additional materials collected during 1903 

 have revealed a very interesting fact, namely, that these animals are 

 closely related to a species discovered long before by an English paleon- 

 tologist, Professor Hulke, and named by him Ichthyosaurus polaris. 

 The demonstration of the identity of this Pacific and extreme north 

 Atlantic form speaks for the continuity of the Pacific and Atlantic 

 oceans in triassic times, and is a fact of interest to geographers as well 

 as to zoologists. 



Dr. F. B. Loomis, of Amherst, who also spent two seasons with 

 American Museum parties, has begun what we may hope will prove to 

 be a series an annual expeditions in behalf of Amherst College. He 

 took his students in 1903 into western Dakota to the ' Titanothere ' and 

 ' Oreodon ' beds, and secured what is reported to be a very fine collec- 

 tion. In 1904 he conducted an exploration into the Wind Eiver Eocene 

 of northern Wyoming, discovering a special deposit of Lower and 

 Middle Eocene fossils in this rather barren horizon. At Amherst Col- 

 lege is the remarkable collection made by the elder Professor Hitch- 

 rock of fossil footprints found along the Connecticut Eiver, which were 

 at first attributed to birds, but are now known to have been made by 

 (dinosaurs. Professor Lull, of the Massachusetts College of Agricul- 

 ture, has been restudying these tracks and has drawn from them some 

 remarkable conclusions as to the mode of life of these ancient denizens 

 of Connecticut, which have been published in the form of a memoir by 

 the Boston Society of Natural History. Professor Lull has also been 

 attached to the American Museum expeditions as a successful field 

 worker. 



The American Museum of Natural History has by no means been 

 inactive during the years 1903 and 1904, having sent out no less than 

 four expeditions, which together have secured two large freight car- 

 loads of fossils. 



The first of the expeditions in 1903, under Mr. J. W. Gidley, was 

 especially searching for the fossil ancestry of the horse in western 

 Nebraska and on the Rosebud and Indian Agency in South Dakota, 

 where a permit was secured. Here the bed of an ancient washout or 

 local flood was discovered containing the remains of a variety of three- 

 foed horses of Upper Miocene age belonging to several species of the 

 genera Protohippus and Neohipparion. No complete skeleton was 

 discovered, but these horses supplement the series found in previous 

 years, and demonstrate one fact of great interest, namely, the coex- 

 istence in western America of at least three entirely distinct kinds of 



