74 KEMP'S ORE DEPOSITS. 



Hardly a bog exists which does not show, when cut in cross sec- 

 tion, the bog ore beneath. Frequent associates of the ore are 

 diatomaceous earth and shell marl, formed by the remains of or- 

 ganisms which once inhabited the waters. At times excellent im- 

 pressions of leaves and shells are preserved in the ore. Such ore 

 bodies are not often practically available on account of the low 

 percentage in iron, due to the abundance of sand and silt washed 

 in, and to the frequent large amounts of sulphur 1 and phosphorus 

 which they contain. The sulphur is present in pyri.te and the 

 phosphorus in vivianite, sometimes in sufficient quantity to be 

 visible (Mullica Hill, N. J., var. Mullicite). In certain parts of 

 the country bog deposits have been and others may yet be utilized. 



2.01.07. In eastern North Carolina bog-ore beds are frequent 

 and are found lying just below the grass roots. Scattered nodules 

 occur in the overlying soil, which are succeeded by a bed three 

 feet or less in thickness, resting on sand. 1 



In Hall's Valley and Handcart Gulch, Park County, Colorado, in- 

 teresting and extensive deposits of limonite are in active process of 

 formation. The iron comes from neighboring great beds of pyrite. 2 



Bog ore of good quality has recently been reported from the 

 vicinity of Great Falls, Mont. 3 



At Port Townsend Bay, in the vicinity of Puget Sound, and at 

 the Patton mines, near Portland, Ore., the ores are of such quality 

 as to be available. 4 (For bog ore in Quebec, see Addenda.) 



2.01.08. A somewhat different variety of Type 1 is formed when 

 the ferruginous waters come to rest in the superficial hollows of 

 the rock which has furnished the iron. Depressions in the serpen- 

 tines of Staten Island, N. Y., carry such deposits, and the iron is 

 referred by N. L. Britton to the leaching of the underlying rock. 

 The ore contains a notable percentage of chromium, which is 

 known to occur in the serpentine. The mines have been in former 

 years quite large producers. Similar limonites occur at Rye, N. Y. 5 



1 W. C. Kerr, Geology of North Carolina, 1875, p. 218. B. Willis, 

 Tenth Census, Vol. XV., p. 302. 



2 R. Chauvenet, "The Iron Resources of Colorado," M. E., June, 

 1889. " Notes on Iron Prospects in Northern Colorado," Ann. Eep. Colo. 

 School of Mines, 1886. 



3 Mineral Resources, U. S. Oeol. Survey, 1888, p. 34. 



4 B. T. Putnam. Tenth Census, Vol. XV, p. 496. 



8 N. L. Britton, School of Mines Quarterly, May, 1881. Compare also 

 Amer. Jour. Sci. y iii., XX. 32, and XXII. 488. 



