410 Expedition to the 



that in these observations we do not intend to apply this 

 name with strict geographical precision to those portions on- 

 ly, which are sufficiently elevated to be called mountains, but 

 so far to extend its signification, as to include not only the 

 high and broken ridges, but several less elevated tracts, pos- 

 sessing the same peculiar mineralogical features. 



The few facts and observations we have it in our power to 

 contribute towards an account of this interesting range, were 

 collected during a pedestrian excursion from Bainbridge on 

 the Mississippi, through the country of the lead mines at the 

 sources of the Meiameg and St. Francis, and a journey from 

 Belle Point, by the way of the Hot Springs of the Washita, 

 and the upper settlements of White river, to Cape Girar- 

 deau. For some important facts we are indebted to Major 

 Long's unpublished journals of tours in various parts of the 

 region in question, and to Mr. Nuttall's *' Travels into the 

 Arkansa territory." 



1. — Carboniferous limestone.* 



We commence with the consideration of this stratum, as it is 

 one of irequent occurrence, and perhaps occupies a greater 

 extent of surface than any other. It so frequently alternates 

 with the micaceous sandstones, and with the peculiar flint rock 

 of this district, that we have never been able to devise any 

 theory of arrangement applicable to more than an inconside- 

 able extent of territory. 



A. few miles west of the rapids of the Canadian, a thin 

 stratum of compact limestone of the common blue variety, 

 and abounding in organic remains, overlays the argillaceous 

 sandstone of the coal formation. This limestone becomes 

 more abundant towards the south, and is the prevailing rock 

 in the country about Red river, near the mouth of the Ki- 

 ameshu.f 



* Couybeare and Phillips apply this name to the limestone of the En- 

 glish coal measures, [p. 340. pi. 1.]. Compact limestone is a name obviously 

 inapplicable to the whole series of calcareous beds, occurring in connex- 

 ion with the coal. 



f The valley of Red river abounds in limestone, often containing shells 

 of oysters and olher rnoiuscous anmials in a state of petrifaction. Similar 

 shells are also seen detached, scattered in profusion over the surface of 

 the ground, retaiuiug their ori;;;inal form entire. On the Arkansa the 

 rocks are generally sanastone, no limestone being to be found, except on 

 the Illinois, Grand, and Canadian rivers. 



Maj. Long's Ms. Journal. 



Among the shells found about Bed river, is one v^hich approaches near- 

 est to the variety of the Gryphaea dilalata of Sowerby, p. 149. fig. 2, but the 



