P Eos 
CARBONIFEROUS — FORT SMITH TO DELAWARE MOUNTAIN. .15 
Lieutenant Simpson, who traversed this region along the Canadian in 1849, makes the fol- 
lowing general observations on its surface: ** Beginning at Fort Smith, a mixed country, well 
watered, composed of wooded heights, wooded plains, and wooded ridges, intermingled with 
SANS BOIS MOUNTAINS 
prairies, some gently rolling some more highly, some of small extent some of large, and all 
generally elongated in the direction of the route and lying between encroaching and parallelly 
disposed secondary mountain heights, characterizes the country as far as Delaware mount, a 
distance of one hundred and forty-six miles." ! 
Coal of good quality appears to be abundant over this section of the line. At Mr. Ring's 
plantation, near Camp 1, a well forty feet in depth crossed a coal-bed three feet thick. (See 
notes.) Coal is also found cropping out at several points along the Sans Bois and Coal creeks. 
Lieutenant Simpson mentions its occurrence on Coal creek, to which it owes its name. ? Near 
Camp 7 it was found in horizontal beds. Characteristic coal-plants, fossilized, were found in 
the beds of the brooks, such as Equisetum giganteum, (August 2,) Sigillaria, (July 19,) and 
again (August 7) between Camps 12 and 13. This last specimen is in the collection, No. 99, 
and is described subsequently. 
- On approaching Delaware mountain Mr. Marcon found, in the bed of Little river, sandstones 
filled with ‘‘ fossils of the lower carboniferous, such as Bellerophon, Crinoids, Productus, and 
bivalves." (Notes, August 13.) Similar fossils were found in the creek at Camp No. 17, and 
hence he concludes that the region of the coal-measures gives place to that of the Lower Carbon- 
iferous between Shawnee valley and Shawnee village. ! í 
! Report of Lieutenant Simpson, of the route from Fort Smith to Santa Fé, page 4. 
? Ibid. 
