124 THE ECONOMIC RESOURCES OF CALVERT COUNTY 



SO far as known the clay has been used for the manufacture of brick in 

 only one locality. It is not suitable for pottery or the finer grades 

 of brick but makes a fairly good variety of common red brick. Since 

 the clay supplies are ample there seems to be no good reason why the 

 county should not produce all the brick and tile of this character required 

 for local uses. Should a ready market be found and better means of 

 transportation obtained, brick for shipment might perhaps be produced 

 at a profit. However, since other counties in the State more favorably 

 situated with respect to markets and the main lines of railroads contain 

 equally extensive clay deposits, sometimes of a better quality, it is not 

 probable that Calvert County will ever become an important clay center. 

 It should, however, produce enough brick to supply the local demand. 



Should the experiments that are being tried elsewhere of using burned 

 clay for road metal prove to be successful some of the clay of the county 

 may be profitably used in this way. Since the sandy roads seriously 

 interfere with the development of the region there will undoubtedly be 

 an increased demand, sooner or later, for cheap road metal, and it is 

 possible that the clay of this region may partially meet this demand. 

 The clays occur in deposits of both Tertiary and Quaternary age. 



Tertiary Clays.— x41 though argillaceous beds occur very frequently 

 in the Eocene and Miocene strata of the State, in general they are too 

 sandy to be of much economic importance. This is especially true of the 

 Eocene in Calvert County. The only important clay member in the 

 Eocene of the State, the pink Marlboro clay, although well exposed along 

 the Patuxent River about four miles north of the county line, here lies 

 beneath tide. It is covered by the arenaceous glauconitic beds exposed 

 in the vicinity of Lyons Creek. 



The Calvert, Choptank, and St. Mary's formations of the Miocene all 

 contain beds of sandy clay which are well exposed in many places along 

 the Calvert Cliffs and in the stream valleys. The Calvert, which out- 

 crops in the northern half of the county, contains more of this clay than 

 do the other Miocene formations, and the clay is less sandy. It is 

 bluish-green to black when fresh, but becomes lighter in color on exposure. 

 It has never been worked and is probably of little economic value because 



