148 Expedition to the 



course with those Indians, until an adjustment of the recent 

 diflv ulties should take place. In addition to the outrage 

 committed on YJr. Saj 's party, they had made prisoners of 

 two white hunters from the Arkansa, a father and son, who 



The curvature of the sides, does not in the slightest degree project be- 

 yond fhe angles of the hinge line. 



13. An imperfect cast, verj like the Terebratula subundata of Sower- 

 by, and of equal magnitude. 



14. Pe.utagon.il ossiculoe of the trunk of Encrinus of authors, which in 

 outline, may be compared to figs. 61 and 62, of plate 13. vol. 2. of Par- 

 kinson's Organic Remains, but their surfaces do not now exhibit any 

 sculpture. 



Many of these shells exhibit the most unequivocal evidences of having 

 been in a plastic state, at some period or other, since their deposition in 

 their present siluafions. The fine striae of a Productus lineolatus, are so 

 interlaced on the middle of a valve of one of our specimens, as at once to 

 convince every observer, of the shell having been thus partially dissolved, 

 and when in this state, to have been gently rubbed by some other body, 

 in two directions i loceeding obliquely to the same point, so as to throw 

 the strias in that part, entirely out of their proper longitudinal direction. 

 It is very common to find shells, unnaturally flattened or compressed in 

 various ways and degrees, often without any fracture in the shell or cast; 

 a circumstance which certainly could never happen to "the shell, unless 

 it was in a plastic state, or in a state of partial solution. 



16. A specimen otcarbonate of lime, on its surface a mass of sub-parallel 

 tubes, connected by short lateral processes. The whole much resem- 

 bles, and is probably congeneric with the Prismatholithus tubiporites, 

 (catenatus) of Mai tin's Petrif. Derbi. t. 42, fig. 2., but the connecting 

 processes of the tubes, are much shorter thau they are represented in 

 that figure ; but it corresponds much more exactly with the tubiponte, 

 figured by Parkinson in his Organic Remains, vol.2, pi. I. f. 1., and 

 may with great propriety, form a new genus, the type of which will be the 

 Tubipora Strues of Lin. 



The gtnus is probably allied to Favosites and Tubipora. 



17. Trilobus. The abdomen of a species of this singular genus, fre- 

 quently occurs in the sandstone ot the Missouri ; near Engineer ( anton- 

 ment they were very common The largest was rather more than one inch 

 long, by ahout 1 3-10 inches in breadth at base, but the more general 

 lengtb is about tiree-fourlhs of an inch. The tergum or intermediate 

 lobe is narrow, being not more than two-thirds of the width of the flanks, 

 and much more convex than those parts. 



But a single specimen oct urred which we can, without any doubt, con- 

 sider as the thoiax of a Trilobus; but whether or not it appertains to the 

 same species with the above, or to some other of which we have no other 

 fragment, we are at a loss to determine. Like the abovementioned ab- 

 domen, it is distinct from any that we have seen figures of. It is of a nar- 

 row lunate form, highly convex, the disk destitute of sculpture, and the 

 eyes prominent. 



18. Many imperfect casts of two different kinds of bivalve shells occur 

 near Engineer Cantonment, of which one may possibly have been a Car 

 dita. 



