196 THE MINERAL RESOURCES OF CECIL COUNTY 



which may have arisen through ignorance of their presence beneath 

 the surface. 



Building-stone. 



The building-stone quarries at Port Deposit, Frenchtown, and less 

 important areas in the county are yielding a large share of the in- 

 come derived from working the mineral resources of the county and 

 probably no industry is on a firmer footing in the community than 

 that of quarrying building- and crushed stone. The stone which 

 is here quarried is placed on the market as a granite although scien- 

 tifically, as described in the preceding paper on the crystalline rocks 

 of the county, it is grouped in the recently established class of igneous 

 rocks, known as monzonites. 



PORT DEPOSIT. 



The largest and most successfully operated quarries within the 

 county are situated at Port Deposit where they support the main in- 

 dustry of the town. The rock at this point as shown in the accom- 

 panying photograph is admirably situated for quarrying and shipping 

 purposes. By the railroad which passes by the quarry there are good 

 connections with Philadelphia, sixty-seven miles distant, Baltimore 

 forty-three, Washington eighty-three and Harrisburg, sixty-five miles. 

 From the wharf nearby may be loaded light-draft vessels which can 

 carry the material without transhipment to Philadelphia, Baltimore, 

 Washington, and Richmond at very low freight rates. The rock-wall 

 rising directly from the level of the water to a height of 200 feet 

 above sea-level offers exceptionally fine facilities for the quarrying 

 of granite without the serious difficulties arising from water and 

 the removal of worthless material, so often encountered in quarries 

 which are sunk below the surface of the surrounding region. 



The value of the granites and the opportunities offered for quarry- 

 ing were early recognized and the rock was used by the settlers for 

 the foundations of some of the old colonial dwellings in the region. 

 The industry arising from the quarrying of the rock is, however, of 

 somewhat later origin. 



In the years 1816-1817 a bridge was built across the Susquehanna 



