. Appendix to the Journals of the Senate and Assembly of the ... session of the Legislature of the State of California. of the high the southern slope of Iron Mountain, there is a variety of igneousrocks, from very acid to basic types, the different types occurring inbelts having a general N. 30° E. strike. The contact between the irondeposit and country rock is usually covered but where observed the lineof demarkation between them is sharp and distinct. However, some large pieces of slide rock show banding of iron withboth acid and intermediate rocks indicating a probable intermin
. Appendix to the Journals of the Senate and Assembly of the ... session of the Legislature of the State of California. of the high the southern slope of Iron Mountain, there is a variety of igneousrocks, from very acid to basic types, the different types occurring inbelts having a general N. 30° E. strike. The contact between the irondeposit and country rock is usually covered but where observed the lineof demarkation between them is sharp and distinct. However, some large pieces of slide rock show banding of iron withboth acid and intermediate rocks indicating a probable interminglingof materials about the edge of the iron mass. On the northwest sideof the deposit the contact rock is of light gray color of an acid type MADERA COUNTY. 557 while rocks of an intermediate character are in contact with the ironat other points. There are no indications of movement at any of the observed con-tacts. Fracturing in a northeasterly direction, parallel to the strikeof the deposit, is strongly developed through the iron mass. FigureB shows the portal of a tunnel that is entirely within the iron mass. Fig. B, Portal of tunnel in massive iron ore on Iron by F. B. Weeks. and the fracturing characteristic of the deposit is here stronglydeveloped. The fracturing is subsequent to the formation of the oreand may be wholly due to shrinkage of the mass prior to its completeconsolidation. In certain narrow belts of the associated igneous rocksschistose structures are developed. No flow structures were slopes of Iron Mountain are covered with slide material composedof the igneous rocks and iron from the deposit. 558 MINES AND MINERAL RESOURCES. The deposit is a mass of iron composed of magnetite in which noother material was observed. Its strike is , and its elevationabout 11,000 feet above sea level. On account of the slide rock noaccurate determination of the surface extent of the deposit could bemade. It was estimated to be 2000 feet or
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Keywords: ., bookauthorcaliforn, bookcentury1800, bookdecade1850, bookyear1853
