Appendix F. 



glossary of tekms. 



JBolian rocks. Fragrnental rocks composed of wind-drifted materials. The "drifb 

 sand rock," the common bnilding stone of Berninda, is a good example. 



Argillaceous. Containing claj-ey matter. 



Ashlar masonry. Cut stone laid in continuous conrses. 



Bardlglio. This is a favorite Italian marble ol)taine(l on Montalto, on the southern 

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

 In some specimens the veining assumes tlic ai)pearanee <jf llowc^rs, when it is 

 known as Bardiglio fiorito. The name is now commonly api)lied to any mar- 

 l)le having this color and veining. 



Bastard granite. A somewhat indetinite name given by qnarrymen to gneissic or 

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

 Tlui name is frequently aj)plied by (|uarrymen to any vein or dike ro(d\ occur- 

 ring in a granite quarry. 



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

 davidsonia), and us?d for making small ornaments. 



Bituminous. Containing liitumen. 



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



Breccias. Fragrnental 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 Districtof 

 Columbia a mica schist; in New York a blue-gray sandstone; in I'ennsylvauia 

 a'blue-gray sandstone. A popularterm ; not snfliciently delinite tobt; 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 cavitiesor pores, due in most cases to the removal 

 of some mineral, or in limestones of a fossil. 



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

 mon in recent eruptive rocks, especially theglassy forms. Sometimes the stoue 

 contains so many cells that it will lloat on water, as is the case with connuon 

 pumice. These cells are in many cases subse(|uently iilled with other minerals, 

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

 (ixanqde of amygdaloidal structure tbnnd in our building stones. 



Choncoidal fracture. Wlien the surfaces of a chip I)roken otf by a Iiannner are 

 curved like a bivalve iiioliusk the stone is said to have a cholicoidal fracture. 

 Compact stor.cs, like lithographic limestones, olisidiaus, and Hints, usually 

 break in tliis manner. 



Clayholes. Caviticis in stones which arc usually tilled with tine sand or clayey ma- 

 teiiiil often of a lighter color than tlxi 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, are 

 elements of wc.-ikness anil should always be avoitled. 



521 



