23S [Mar, 1845. 



self to judge, whether an increase of the heat, short of that necessary to produce 

 vitrification, may not have converted the mass into the red pumice of the 

 Missouri. 



In a bed of soft sandstone at the mouth of Cannon Ball River, great numbers 

 of those singular stones are found, which give name to the stream. The fol- 

 lowing remarks from my Journal, made on the passage up the River, were 

 fully confirmed when we stopped at the mouth of Cannon Ball River on our 

 return. " June 6 — On passsing the mouth of Cannon Ball River yesterday, we 

 noticed a remarkable formation in this stratum" (soft sandstone) « of round 

 masses of rock" (Hard sandstone) " in the divisions of the strata, many of them 

 apparently perfectly spherical, and from 18 to 30 inches in diameter, some as 

 perfect as cast balls, others appear to be flattened or composed of two sections of 

 a sphere, from a smaller ace up to a hemisphere, joined together with mathema- 

 tical nicety, and surrounded by a belt or zone at the junction projecting from 

 one to four inches, which zone lies horizontally in the line of division of two 

 strata. I had observed traces of this peculiarity in the rock the day before, and 

 this evening, 30 miles below the Mandans, I noticed it again. Cannon Ball 

 River takes its name from the presence of these balls. They are said to be 

 hollow, and to contain crystals." The last remark was not confirmed by the 

 opening of two large specimens brought home by Mr. Audubon, which were 

 found to be solid and of uniform texture throughout. 



A somewhat analogous formation occurs in the region of the Yellowstone. 

 It consists of a similar hard sandstone, lying also in the divisions of the strata 

 of soft sandstone, but in form like a flattened trunk of a tree swelling out at the 

 root, and might be taken for fossilized wood, but that it is destitute of concen- 

 tric rings, and laminae can always be traced in the direction of the longest dia- 

 meter of the elliptical end, sometimes in exact correspondence with, and in 

 other instances lying obliquely to, that diameter. I have seen them in situ 

 projecting ten feet horizontally and perpendicular to the face of the cliff. I 

 have seen others of more than twenty feet in length lying at the foot of the 

 cliff whence they had fallen. The smaller end always exhibits the appear- 

 ance of a transverse fracture with edges sharp and well defined, the larger 

 end rounded and resembling the head of an immense bone fitted to work in 

 a socket. 



If this meagre statement of facts and the few specimens which accompany 

 it, will serve in a small degree for the better appreciation of the Geologicial 

 character of this interesting region, and hold out any inducement to well qua- 

 lified persons to undertake its investigation, the object of the undersigned will 

 be accomplished. 



Yours Respectfully, 



Edward Harris. 



