MINERAL PAINT. 357 



at Grove contain the necessary ingredients for the manufacture of Port- 

 land cement, and tliat by a simple process these ingredients can be com- 

 bined in a suitable mixture. 



Tlie occurrence in the Virginia Coastal Plain of extensive beds of 

 calcareous marls and clays suitable for cement making and which can be 

 readily and cheaply dug, combined with the advantage of location of 

 plants readily accessible to ocean steamers, the cheapness of labor, the 

 mild climate which permits of working in the open air practically the 

 entire year, and the proximity to the coal fields, unite to make this an 

 unusually advantageous area for the manufacture of Portland cement. 



MINERAL PAINT. 



Brown hematite is frequently present in such large quantities in the 

 Potomac and Lafayette clays as to form an impure ocher. Locally such 

 deposits might be profitably worked, although little attempt has been 

 made to develop them in Virginia. Limonite is present in certain beds 

 in the Miocene in such amounts as to stain them a bright ocher yellow. 

 Frequently it is found in small patches and almost pure but only in few 

 places does it occur in large enough masses and sufficiently pure to be of 

 much value. 



Although ocher of more or less purity occurs in a number of places 

 in the Virginia Coastal Plain region, attempts to mine it have been con- 

 fined to the extreme eastern part of Chesterfield County, 4 miles southwest 

 of Bermuda Hundred, on the Appomattox Eiver. The material is an 

 excellent grade of yellow ocher and was extensively mined for a period of 

 years beginning in 1872, by the American Ocher Company. A high grade 

 ocher was produced, the production amounting to 1,000 tons in 1880. It 

 is said to have been considered by consumers preferable to the Rochelle 

 product and to have materially lowered the market price of all foreign 

 ochers. As a result of the competition, Eochelle ocher fell in price from 

 3% to 11/4 cents per pound. The mine was worked by tunnels extending 

 into the hill from the bluffs of the river. The deposit was reported to 

 have been about 7I/2 feet thick and is in the upper strata of the Calvert 

 formation. 



Three grades were made, all of the same grade but of different degrees 

 of fineness, namely, "single washed," "double washed," and "extra fioated." 

 At the shipping point in Virginia, these grades have a value respectively 



17 



