34 PROCEEDINGS OF THE ASSOCIATION OF 



selves in alternate succession. In the vicinity of the Platte river, as 

 well as at Council Bliilij a limestone containing Cyathophylla oi^ large 

 size, Encrinitcs, and other fossils, appears in a position seemingly be- 

 tween the clilf limestone and the coal. Near the confluence of the 

 Sioux river and the Missouri, there occurs a formation overlaid by 

 a thick deposit of clay, containing, in abundance, several species of 

 Ammonites and JBaculites, Belevinites, Inocerami, &c. &c., beautifully 

 raised on their exterior and sparry in their interior. Some of them 

 were exhibited to the meeting. These fossils were identified with 

 similar ones belonging to the green sand deposit of New Jersey, a 

 member of the chalk series ; but no true chalk or flint (silex pyro- 

 mage) was observed. The occurrence of this formation had already 

 been indicated, by some fossils that Lewis and Clark and Mi*. 

 Thomas Nuttall had In-ought along with them from their travels, 

 and which were described by Dr. Morton. Mr. N. cxliibited further, 

 some fossil bones ■which had been submitted to the inspection of Pr. 

 Harlan, w^ho describes them as being vertehrce of a Squalus and 

 of a nondescript crocodile ; also articulated vertebrfe of an animal 

 referable to the order Enalio-sauri of Couybeare. The surface pre- 

 sented by a transverse section of these vertebrie, Dr. H. thinks pecu- 

 liar, as also the mode in which the ribs are attached to a small pro- 

 cess in the middle of the inferior surface of each vertebra. From 

 their size and unique character, it is quite probable that these verte- 

 brcB form a part of the skeleton of the tSauro-cepliahis lanciformis, 

 (Harlan,) an animal possessing still more of the fish than the lizard, 

 than exists in the organization of the IcJdJtyosauiiis, in which res- 

 pect these vertebra? correspond. According to Dr. Harlan, similar 

 fossils have been found in the green sand of New Jersey and in the 

 chalk of England. 



Mr. Nicollet concluded by remarking, that he had followed up 

 and descril^ed this formation, along an extent of upwards of four 

 hundred miles, and from information received and from fossils that 

 had been furnished to him, thinks that it extends to the west at least 

 as far as the sources of the rivers Running Water, White, Shayeune, 

 &;c. and northwest along the Missouri probably to the Yellow Stone, 

 being an extent in length of about one thousand miles. 



Mr. Hodge followed with some observations concerning the 

 secondary and tertiary deposits of the Carolinas, which he inten- 

 ded to imbody in a paper for publication. 



Mr. Hodge proceeded to notice the deceptive appearance of 

 the bowlders of <]uartz and primary rocks, scattered over the country 

 north of Columbia, S. C, and extending throughout the gold region 

 of North Carolina, nil scemingJy referable to a similar cause with 

 that Avhich covered the hills of the northern states with their bowl- 

 ders. But according to the previously expressed opinions of Messrs. 

 Vanuxem and Mather, these are considered not to have been trans- 



