26 Siouj- Citij Academy of Science and Letters. 



several miles north of Sioux C\tj. When down about 

 six feet below the surface in the hard blue clay of the 

 Cretaceous period they came upon some fossil bones. 

 Fortunatelj'^ the owner of the farm, Mr. D. H. Talbot, 

 was sent for at once, and being an enthusiastic student 

 of science the find was carefully taken out and all parts 

 preserved. It proved to be the remains of a large sau- 

 rian or reptile, something like the alligators still living 

 in the waters of our southern states. During the Creta- 

 ceous period the huge reptiles, which became so numer- 

 ous in the succeeding Tertiary age, began to make their 

 appearance, and these fossil bones were the remains of 

 one of them. It was an animal with a body as large as 

 that of an ox, having a long flexible neck, while its head 

 was not larger than that of a medium sized dog. It was 

 a flesh-eating animal, its mouth being filled with sharp, 

 conical teeth. This one, the remains of which we have, 

 was not far from twenty feet long, as we know from the 

 number of vertebrae found, which was eighty-one. It 

 had four legs or swimming paddles, short and massive. 

 These remains were sent to the eminent scientist, O. C. 

 Marsh of Yale College, who pronounced the animal to 

 have been, in all probability, a Plesiosaurus. These rep- 

 tiles lived in the salt marshes bordering the great ocean 

 that at that time covered the interior of our continent. 

 It is probably a new species and has been named Plesio- 

 saurus Hoskinsi from our esteemed fellow member, Mr. 

 J. C. C. Hoskins, who helped preserve the fossil remains, 

 and who first described it when found. This is one of 

 our most valuable specimens. 



The chambered nautilus is one of the most beautiful 

 sea shells now living. Back a hundred million years in 

 time the first fossil shells of this family are found. These 

 first ones from the Trenton period of the Lower Silurian 

 had plain smooth partitions between the chambers, but 

 as time went on these septa or partitions became folded 

 in more complex shapes until, in the Ammonites of Cre- 

 taceous times, they were folded in the most complex 

 convolutions. We have many specimens of such fossils 

 in different genera and species. The Ammonites were 

 coiled flat like the Nautilus, and were from an inch to 



