84 Expedition to the 



• 



and it is not, perhaps, improbable that his efforts may have 

 somewhat hastened the termination of his life. 



Between Loutre island *and Cote Sans Dessein, compact 

 limestone occurs, in hori2ontal strata, along the sides of the 

 Missouri valley. It is of a bluish white colour, compact 

 structure, and a somewhat concoidal fracture, containing few 

 organic remains. It alternates with sandstones, having a si- 

 licious cement.* These horizontal strata, are deeply covered 



* From Bay Charles hill, 4 miles below Hannibal, Missouri, we receiv- 

 ed, through Dr. Sommerville, several organic remains. Among them are 

 the following : 



Carbonate of Lime : 



One specimen contains exclusive quantities of segments of the Encri- 

 nite of small diameter, from 1 -4 of an inch down to miuute. 



Another specimen also with numerous small Encrinites has a very 

 wide and short radiated Productus. 



Another specimen a grayish chert, containing cavities formed by the so- 

 lution and disappearance of encrinites, the parts of these which were ori- 

 ginally hollow when in the state of carbonate of lime, being subsequently 

 filled with chert, now show the nature of the fossil, being cylindrical ca- 

 vities, with a solid centre and transverse partitions— the largest 3-10thsof 

 an inch wide. 



From Rector's hill, adjoining the village of Clarksvillc, Missouri, from 

 Dr. Sommerville's collection : 



A specimen of oolite — carbonate of lime. 



It is composed of small spherical granules in contact with each other, 

 which, in their fracture, exhibit rather a concentric tendency, with theap- 

 pearance of a central nucleus; but we could not perceive any decided evi- 

 dences of former organization in them. Imbedded in the mass are a few 

 columnar segments of encrinites, and a portion of a compressed bivalve, 

 which, in the form of its radiating lines, resembles a pecten. 



From Charboniere : 



A specimen in argillaceous sandstone of a portion of a leaf like the 

 Nelumbium — It is only the middle portion of the impression of the leaf 

 that remains, being of an oval form of about five inches in greatest di- 

 ameter, the rest being broken away : the stalk has been broken off at the 

 junction of the leaf. 



Productus spinosus. Say. 



A small species of terebratula, in width two fifths, and in length more 

 than seven-tenths of an inch — an internal cast — individuals very numer- 

 ous, varying much in size, the smallest being about one-fifth of an inch 

 wide. 



From the Mammelles near St Charles : 



Productus : a portion of a valve, and smaller portion of the oppo- 

 site valve of a remarkably large species, of *vhicb the proportions may 

 have been not dissimilar to that of the Ency. Meth. pi. 244, fig. 5— the 

 striae are similar to those of that shell, except in being somewhat 

 smaller, and the groove of one valve, and consequent elevation of the 

 other, not so profound, less abrupt, and more angular in the middle, and 



