MARYLAND GEOLOGICAL SURVEY 127 



exposed through wave-cutting along the Bay and the Patuxent Eiver in 

 the southern portion of the county. They are seen one-half mile north- 

 east of Drum Point, one-quarter mile west of Drum Point, and one-half 

 mile south of St. Leonard Creek. Similar clays occurring at Bodkin 

 Point near the mouth of the Patapsco Eiver have been tested and de- 

 scribed by Dr. Heinrich Ries.' He states that the clay "burned to a 

 good red color under ordinary conditions and to a deep brown when 

 \'itrified. Before this clay could be used in large ware it would be 

 necessary to add sand to prevent excessive shrinkage." In certain out- 

 crops these clays contain sufficient vegetable material to render them unfit 

 for use but in others they contain very little organ ii' matter. 



THE SANDS. 



Since the arenaceous phase predominates in almost every formation 

 represented in the region, the county contains an unlimited supply of 

 sand. The sand of the Pleistocene is used locally for building purposes, 

 but since it is so readily obtained in all parts of the county no pits of 

 any considerable size have been opened. It is said to be a fairly good 

 building sand yet no better than quantities of sands in other parts of the 

 State, hence the demand for it is purely local. 



In some places the quartz sands of the Miocene seem to be pure enough 

 for glass-making, suggesting the Miocene glass sands so extensively ex- 

 ploited in southern New Jersey, although they have never been used for 

 that purpose in this region. Careful chemical analyses and physical 

 tests, which have not been made, would be required to determine their 

 usefulness in this respect. 



Locally, the Pleistocene sands are rich in ferruginous matter which, 

 in places, cements the grains together forming a ferruginous sandstone. 

 Sands of this character possess a distinct value for road-making pur- 

 poses, as they pack readily and make a firm road bed. Where the 

 material can be easily obtained in large quantities good roads of this 

 kind can be very economically constructed. The ferruginous sands are 

 best developed in the Sunderland formation, principally because of the 



'Md. Geol. Survey, vol. iv, 1902. 



