33 [ 237 J 



&c. At the last mentioned locality, on the limestone over which the creek 

 called Gabouri flows, the tnrbinolia fungites and a new species of prodiicta 

 are found associated with the bellerophnii hiulcns, as well as other species; 

 and they are all mineralized into red chalcedony. 



The upper strata of this Gabonri limestone present a beautiful rock 

 with an oolitic structure, which is now quarried for architectural purposes. 

 It is, doubtless, an equivalent of that which occurs in the Burlington group, 

 Iowa. It extends itself to the right and to the left of the Mississippi, to near 

 the Ohio river, and even through Kentucky and Tennessee. My venera- 

 ble friend, Dr. G. Troost, the geologist of the State of Tennessee, was the 

 first who discovered this rock, and very sagaciously pointed out that it had 

 no geological relation with the great ooVilic fo7'maf.ion of Europe. The 

 fossils cont;dned in the oolitic limestone of the Gabouri are obscure and un- 

 determinable ; but, in oiher localities, this rock has yielded pentremites 

 pyriformis^ peiitre/nites fflobosus, pe7if?'cm.itesflorealis, that have been de- 

 scribed by Say, and a fourth species, which is new. 



I have deemed the foregoing digression necessary in order to connect 

 the geology of the country just described, with a more recent formation 

 previously alluded to, with which I am to meet in ascending the Mis- 

 souri. 



Leaving Council Bluffs, the hills on either side are observed to be at a 

 greater distance from the river, which is itself twice its preceding width. 

 The valley is fully fifteen miles wide ; and the broad prairies that carpet it 

 exhibit the same richness of soil and luxuriance of vegetation as those I 

 have already had occasion to describe. The bends on the river have 

 courses of longer radii, and are more multiplied, so as greatly to increase 

 the travelling distance between two spots. The width of the river varies 

 from one-fitth of a mile to two miles. In its widest parts, the navigation is 

 frequently impeded by sand bars and drift-wood ; but, where it narrows, 

 the current flows in a straight, onward direction, between picturesque 

 banks or passages, such as may be seen at the mouth of Little Sioux river. 

 But in those instances, it is easy to discover that these passes are cut off 

 through some of the bends. Thus we could not recognise many of the 

 bends described by Lewis and Clark ; and, most probably, those deter- 

 mined by us in 1839, and laid down upon my map, will ere long have 

 disappeared ; such is the unsettled course of the river. Already have I 

 been informed, in fact, that the great bend opposite Council Bluffs has 

 disappeared since our visit ; and that the Missouri, which then flowed at 

 the foot of the bluff, is now further removed by several miles to the east of 

 it. It is, in this respect, curious to compare our journal of travelling 

 distances with that of Lewis and Clark. They are found always to differ, 

 and sometimes considerably. Yet, on arriving at any prominent station, 

 as the confluence of a large river, the amount of the partial distances com- 

 puted agree as nearly as could be expected from the methods employed to 

 estimate them. 



After a navigation of two days, the hilly country, which had receded 

 from us since our departure from Council Bluffs, came again into sight, and 

 we stopped at the foot of the bluff on the right side of the river. This 

 place affords a beautiful site, formerly occupied by a Mr. Wood, an Indian 

 trader ; and it still bears his name. Having reached this place by night, 

 and as it was fixed that the steamboat was to leave the next morning be- 

 fore day, being very anxious to know whether the geological character o ^ 

 3 



