NATURAL HISTORY MUSEUMS 65 



4 polished granite risers 7 feet by 1 foot 6 inches and 4 large 

 turned columns of granite, marble, serpentine and red sand- 

 stone, a collection of polished slabs of ornamental marbles 8x4 

 and 4x4 inches and slabs of polished marble and serpentine 

 40 X 30 inches. There are also other columns and blocks of 

 granite, serpentine, etc. The Triassic breccia, known as the 

 Potomac marble, from Frederick county is represented by a 

 large polished column, slabs, blocks and partially polished 

 boulders, and the slate of Hartford county by a series of speci- 

 mens of rough blocks, split and finished slates. Samples of 

 road-making rocks are shown with the results of tests to which 

 they are subjected. A series of tested specimens from all avail- 

 able quarries in the state are kept in storage. 



The other room contains principally' clays and clay products. 

 A series of clays from all the principal producing localities is 

 kept, a tj'pical collection being exhibited in glass jars. Pottery 

 is well represented from most of the Maryland producers, terra 

 cotta is shown in ornamental pieces and such blocks as are com- 

 monly used in building construction; gas retorts, furnace 

 blocks, fire brick, stove lining and glazed bricks show the uses 

 of fire clay, pressed brick are shown in the construction of an 

 ornamental mantel and in panels. There is also a series of 

 sands, ground quartz, talc, etc., shown in jars and a set of the 

 most typical soils of the state are shown in bulk and divided 

 into their component parts of gravel, sand, silt, clay, etc. 



There is a reserve series of coal specimens kept in jars and 

 the results of their analyses. The series of coals on exhibition 

 consists of large cubes representing the principal coal seams of 

 the state. Relief and geological maps and transparancies 

 occupy the windows and wall space. 



There is a geologic library of over 1000 volumes consisting 

 largely of official reports of the national and state surveys. 



Rock Hill college museum, Ellicott City. The Rev. Bro. Fabri- 

 cian F. S. C. in charge. 



Blineralogtf. 2000 specimens for educational purposes. Used 

 specially in connection with the study of chemistry. 



