212 APPENDIX. 



dently offer indubitable proofs of the occuiTence of the Devo- 

 nian rocks on the Missouri River. 



" In latitude 40^ 50^ and longitude 95° 42' from Green- 

 wich, eighteen miles below Platte River, there is a locality- 

 known by the name of ' Five Barrels Island.' Opposite to 

 that group, and on the right side of the river, a bluff, at the 

 termination of a series of rocky banks, is separated by a 

 small creek from another series called Cotes de la Platte. 

 At the base of the bluff there is — 



" 1st. A compact argillaceous limestone of a bluish color, 

 from one to two feet thick ; soft under water, but hardening 

 when exposed to the air ; it weathers into thin plates, pre- 

 senting an uneven surface ; on which there are impressions 

 of euomphali, but too indistinct to be specified. 



" 2d. A compact argillaceous limestone of a yellowish- 

 grey color, from six to seven feet thick, containing an abun- 

 dance of crinoidal remains, associated with beautiful and large 

 specimens of the cyathophyllum vermiculare of Gold. This 

 limestone also contains a producta and an unknown bivalve, 

 together with crystallized bi-sulphuret of iron agglomerated 

 into bullets. 



" The uppermost portion of the bluffs, attaining a height of 

 180 feet above the river, I remarked to be shadowed by trees 

 over a beautiful green sward ; but I had no opportunity of 

 examining it particularly. 



" It may be well to state here, that all such rocky banks 

 as the one just alluded to, noticed by Lewis and Clark, and 

 subsequently by Major Long, are constantly wearing away ; 

 so that they offer landmarks to the traveller only for a limited 

 period of time. But we are not to judge of their orycto- 

 gnostical character from the detritus found below tliem ; be- 

 cause this is composed not only of the materials derived 

 from the bluffs, but of others earned down the Missouri 



