. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. HANDBOOK FOR THE DEPARTMENT OF GKOLOGY. 545. Geological age and mode of occurrence.—The limestones are metamor- phosed chemical deposits or sedimentary beds occurring associated with rocks of all ages, from the earliest to the most recent. They are considered in large part as rocks composed of the metamorphosed debris of mol- lusks, corals, and other lime- secreting animals. In the pro- cess of metamorphism these remains may have been com-
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. HANDBOOK FOR THE DEPARTMENT OF GKOLOGY. 545. Geological age and mode of occurrence.—The limestones are metamor- phosed chemical deposits or sedimentary beds occurring associated with rocks of all ages, from the earliest to the most recent. They are considered in large part as rocks composed of the metamorphosed debris of mol- lusks, corals, and other lime- secreting animals. In the pro- cess of metamorphism these remains may have been com- pletely obliterated as in the Vermont marbles (specimen 17345), or may still be in part preserved though the entire mass has taken on a crystalline structure, as in numbers 35804, 35805, 35907, G9253, etc. To Fig. M. the paleontologist this group Micro-structure of Crystalline Limestone;. Of rOCks iS One Of Very great (West Rutland, Vermont.) importance, owing to their fossil remains. From an economic stand- point they are also of value, furnishing quantities of material for gen- eral building as well as beds of finest marble for ornamental work. (See building and ornamental stone collections.) Classification and nomenclature.—It is common to speak of this entire group of rocks as simply limestones, though many varietal names are often rather indefinitely applied. The name marble is applied to any calcareous or magnesian rock sufficiently beautiful to be utilized in decorative work. Argillaceous and siliceous limestones carry clayey matter and sand. Hydraulic limestones contain varying proportions of magnesia, alumina, silica andiron oxides. Such furnish, when burned, a lime with the property of setting under water and known as hydraulic cement. (Specimens 39809 from Roseudale, Ulster County, New York.) Dolomite (so named after the French geologist Dolomieu) is a rock con- sisting of per cent, carbonate of magnesia and carbonate of lime. (Specimens 37662, 35906,
Size: 1586px × 1576px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorsmithsonianinstitutio, bookcentury1800, bookdecade1840
