sharp has been sold as low as $3.50 per ton. About seventy-five per cent. of the product of the mills is sold for plaster purposes and the total product for 1901 was about 125,000 tons.
The lead and zinc is all produced in the counties of Dubuque and Allamakee. The amount of zinc produced in 1901 was three hundred and fifty tons and of lead ore the product was 13,800 tons.
The only county producing iron ore is Allamakee. The only body of ore thus far developed is at Iron Hill, the highest point in the county which rises to a height of two hundred feet above the water level of the Oneota River, three miles northeast of Waukon.
Iowa in 1901, ranked eighth as a clay producer among the States of the Union. The number of tons of coal mined in 1901 was 5,663,016, sold at an average price of one dollar and forty-two cents per ton. The average number of men employed was 13,032; and Iowa ranked ninth in tonnage and sixth in the value of coal produced in the United States in the year 1900.
| Clay products used for making brick and tile valued at | $2,774,200 |
| Stone quarried, lime manufactured | 781,756 |
| Gypsum | 562,500 |
| Lead and Zinc | 16,500 |
| Iron ore | 4,876 |
The number of producers were of | |
| Coal | 242 |
| Clay | 349 |
| Stone | 229 |
| Gypsum | 7 |
| Lead and Zinc | 10 |
| Iron ore | 1 |
