Page:Popular Science Monthly Volume 67.djvu/570

564 like tail, smooth, scaleless skin, very effective, dolphin-like paddles, and long, pointed snout. Dr. Merriam at first regarded Shastosaurus as a segregated or isolated type which developed from some more primitive 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 paleontologist, 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 collection. In 1904 he conducted an exploration into the Wind River Eocene of northern Wyoming, discovering a special deposit of Lower and Middle Eocene fossils in this rather barren horizon. At Amherst College is the remarkable collection made by the elder Professor Hitchcock of fossil footprints found along the Connecticut River, which were at first attributed to birds, but are now known to have been made by (dinosaurs. Professor Lull, of the Massachusetts College of Agriculture, 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 carloads 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 threefoed 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 coexistence in western America of at least three entirely distinct kinds of