Appendix F. 



GLOSSARY OF TERMS. 



iEolian rocks. Fragmental rocks composed of wind-drifted materials. The "drift 

 sand rock," the common building stone of Bermuda, is a good example. 



Argillaceous. Containing clayey matter. 



Ashlar masonry. Cut stone laid in continuous courses. 



Bardiglio. This is a favorite Italian marble obtained on Moutalto, on the southern 

 borders of Tuscany. It is a gray or bluish color, traversed by dark veins. 

 In some specimens the veining assumes the appearance of llowers, when it is 

 known as Bardiglio fiorito. The name is now commonly applied to any mar- 

 ble having this color and veining. 



Bastard granite. A somewhat indefinite name given by quarrymen to gneissic or 

 schistose rocks, resembling granites in a general way, but differing in structure. 

 The name is frequently applied by quarrymen to any vein or dike rock occur- 

 ring in a granite quarry. 



Bird's-eye-marble. A term used in Iowa to designate a fossil coral (Acervularia 

 davidsonia), and used for making small ornaments. 



Bituminous. Containing bitumen. 



Breast. The face or wall of a quarry is sometimes called by this name. 



Breccias. Fragmental stones, the individual particles of which are large and angular 

 in form. 



Bluestone. In Maryland a gray gneiss; in Ohio a gray sandstone ; in the District of 

 Columbia a mica schist; in New York a blue-gray sandstone; in Pennsylvania 

 a blue-gray sandstone. A popular term ; not sufficiently definite to be of value. 



Butt. The butt of a slate quarry is where the overlying rock comes in contact with 

 an inclined stratum of slate rock. 



Calcareous. Containing lime. 



Cavernous. Containing irregular cavities or pores, due in most cases to the removal 

 of some mineral, or iu limestones of a fossil. 



Cellular or vesicular. Containing cells or vesicles. This structure is very com- 

 mon in recent eruptive rocks, especially the glassy forms. Sometimes the stone 

 contains so many cells that it will float on water, as is the case with common 

 pumice. These cells are in many cases subsequently filled with other minerals, 

 and the rock is then called amygdaloidal. The Brighton melaphyr is the best 

 example of amygdaloidal structure found in our building stones. 



Choncoidal fracture. When the surfaces of a chip broken off by a. hammer are 

 curved like a bivalve mollusk the stone is said to have a choucoidal fracture. 

 Compact stones, like lithographic limestones, obsidians, and flints, usually 

 break in this manuer. 



Clayholes. Cavities in stones which are usually filled with fine sand or clayey ma- 

 terial often of a lighter color than the stone itself and so loosely coherent as to 

 fall away immediately or to weather out on exposure. They are especially 

 prevalent in many of our Triassic sandstones, and, besides being unsightly, aro 

 elements of weakness and should always be avoided. 



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