SURVEY OF COLOEADO AND NEW MEXICO. 93 

 DEPOSITS OF COiU:. AND IRON ORE. 



One of the most important problems to be solved in tlie West is the 

 utilization of the vast quantities of iron ore which are scattered all over 

 the country in a multiplicity of forms. The brown iron ores accompany 

 the coal beds everywhere, and some good deposits are found in the cre- 

 taceous formations. At the source of the Chugwater are immense de- 

 posits of magnetic iron ore in the metamori)hic rocks, which are prob- 

 ably of Laureutian age, while at Eawlings's Springs are most valuable 

 beds of the red oxide of iron, in rocks which I suppose to be of triassic 

 age. The latter are evidently local, but the amount of iron ore is con- 

 siderable. 



The following extract is taken from the excellent report of Dr. John 

 L. Leconte to the Pacific Eailroad Company : 



"Deposits of iron ore fit for working are found in the sandstones of 

 the Vermejo, as described on page 24 of the first part of the report. Veins 

 of specular, titaniferous, and magnetic ore, occur in the metamorphic 

 rocks of the mountains; those nearYegas are mentioned on page 29. 

 Large quantities of magnetic iron are found near the Ortiz mine, and 

 beds of an argillaceous variety occur near the anthracite of the Placer 

 Mountain, as mentioned on page 39. 



" Should the coal be capable of use for smelting iron, the localities of 

 the latter will be found ample for all possible demands. 



"I have received from Messrs. Williams and Moss the following results 

 of the examination of some iron ores collected on the journey: 



1. Magnetic iron ore, Las Vegas, metallic iron 20.43 per cent. 



2. Magnetic iron ore, Placer Mountain, metallic iron . . 65.27 per cent. 



3. Carboniferous iron ore, Vermejo Caiion 21.91 per cent. 



4. Carbonate of iron, near anthracite of Placer Mountain 36.49 per cent. 

 I take the liberty of introducing in this connection the following 



extracts from an article written by me and published in Sillimau's Jour- 

 nal, March, 1868. This paper has been very extensively copied, and 

 even now 1 find it necessary to make but few changes: 



Mines Lave "been opened on Coal Creek, three miles south of Marshall's mines, but 

 they have been abandoned for the present. Another has been opened about twenty 

 miles south of Cheyenne City, on Pole Creek. The drift bepjan with an outcroi)ping of 

 about four feet eight inches in thickness, inclination twelve degrees east. The lignite 

 grows better in quality as it is wrought further into the earth, and the bed, bj"- following 

 the dip two hundred feet, is found to be five feet foxir inches thick, and the lignite is 

 sold readily at Clieyenne City for twenty-five dollars per ton. The beds are so concealed 

 by a sux^erficial drift deposit, that it is difficult to obtain a clearly connected section of 

 the rocks. A section across the inclined edges of the beds eastward from the mountains 

 is as follows : 



7. Drab clay passing up into areno-calcareous grits composed of an aggregation of 

 oyster shells, Ostrea suMrigonaUs. 



6. Lignite — 5 to 6 feet. 



5. Drab clay — 4 to 6 feet. 



4. Reddish, rusty sandstone in thin laminae — 20 feet. 



3. Drab arenaceous clay, indurated- — 25 feet. 



2. Massive sandstone — 50 feet. 



1. No. 5 cretaceous, apparently passing up into a yellowish sandstone. 



The summit of the hills near this bed of lignite is covered with loose oyster shells, 

 and there must have been a thickness of four feet or more, almost entirely composed of 

 them. The sijecies seems to be identical with the one found in a similar geological 

 position in the lower lignite beds of the Upper Missouri near Fort Clark, and at the 

 mouth of the Judith Eiver, and doubtless was an inhabitant of the brackish waters 

 which must have existed about the dawn of the tertiary i^eriod in the West. No other 

 shells were found in connection with these in Colorado, but on the Upper Missouri 

 well-known fresh-water types exist in close proximity, showing that if it proves any- 

 thing, it rather affirms the eocene age of these lower lignite beds. These lignite beds 



