62 GEOLOGICAL RECONNOISSANCE 
a 
crevices in the rock, on the extreme northern confines of Arkansas, and 
form this immense spring, which constitutes the head of the principal 
branch of Spring river, watering the north-east corner of Fulton county; 
and then, entering Lawrence, it forms one of the main streams of that 
county; flowing, finally, into Black river, above Smithville. 
Since the death of the former proprietor, Mr. Mills, the ownership of 
the spring, and the land around, has reverted to his heirs. 
For the sake of the interests of the country, we hope this water-privilege, 
possessing so many natural advantages, will soon be improved in the 
manner its intrinsic value justifies, and that it may fall into the hands of 
enterprizing and practical manufacturers, who will give an impetus to 
profitable and useful branches of manufacturing industry, suited to the 
resources of the country, which soon attract around them an industrious, 
progressive, and intelligent population. 
Extensive deposits of iron ore have been reported as occurring in 
the vicinity of the Mammoth spring. I found some superficial specimens 
of good ore in the north part of Fulton county, but have not seen any 
extensive beds; those referred to by Mr. Mills, in a notice issued of his 
property, before his death, are, probably, situated north of the state line, 
on the western fork, in Missouri. The geological formation is such as{to 
justify the expectation that a detailed survey of Fulton county may dis- 
close bodies of ore that might warrant the erection of furnaces. 
Descending south from the head of Main Spring river, I found the 
country mostly constructed of low chert ridges, with prairie coves between 
them; the timber being, chiefly, on the ridges, of a small growth of oak 
and hickory. e 
Two miles east of the Mammoth spring, a fine, white sandstone* crops 
out on a slope on the Missouri side of the line. 
On Jaynes’ creek, the same kind of country prevails. In the valley of 
that stream, low benches of rugged, weathering magnesian limestone are 
seen projecting from the slopes of the ridges, which are mostly strewed 
with chert blocks, and gravel in the upper portions. The highest of these 
chert ridges are from 250 to 280 feet above the water courses, but the most 
of them are considerably lower. 
* This is probably the equivalent of the sandstone represented on No. 4, which underlies the 
marble limestones of Carroll county. 
