22 Report on the projected Survey of the State of Maryland. 



ring near the mouth of the Seneca. The splendid aqueduct over the 

 Monocacy is constructed of the freestone, quarried at the foot of the 

 Sugarloaf mountain. 



The conglomerate, so well known as the Potomac breccia marble, 

 occurs along the river side, commencing a short distance above the 

 mouth of the Monocacy and reaching nearly to the point of rocks. 

 This formation extends along the valley on the eastern side of the 

 Catoctin mountain, to within two miles westward of Frederick town. 

 It is there contiguous to the red sandstone and blue limestone, by 

 which it is displaced ; but it re-appears in a distance of fifteen miles, 

 near Mechanicsburg. 



The slaty rocks of the present division, which occur east of the 

 Monocacy within the limits of transition from the primary to the 

 groupe of arenaceous rocks, cannot, under existing circumstances, 

 be said to offer any consideration of much moment. Quarries of 

 roofing slate, however, have been opened in several spots — on Bush 

 creek adjoining the line of the Baltimore and Ohio Rail Road ; in 

 the neighborhood of Unionville, &zic. &;c. 



The results of a minute geological examination should, no doubt, 

 exhibit every circumstance of any consequence growing out of the 

 mineral constitution of the country, but there are particular spots giv- 

 ing rise to considerations of such superior interest, that, in a general 

 reconnoissance, the attention is forcibly directed towards them. This 

 is the case with that portion of Frederick county, which may for dis- 

 tinction's sake be called its metalliferous region, lying east of the 

 Monocacy and extending between Bush creek and Finey run. The 

 metals that occur within it are copper, iron, lead and manganese. 



Veins of copper ore had, from a very early period in the settle- 

 ment of our state, been traced through many portions of the country. 

 Upon our oldest maps is found indicated the existence of a copper 

 mine near the Monocacy, between Piney run and Pipe creek. And 

 more recently, the ore has been largely extracted between Liberty- 

 Town and Woodsborough. In fact, it has been observed in all direc- 

 tions, and may be said to exist throughout this region. It occurs in 

 the neighborhood of New Market, associated with an ore of manga- 

 nese ; on the Linganore in various places ; and in the vicinity of 

 New London on the New Market and Liberty road. But its prin- 

 cipal deposites appear to be between Woodsborough and Liberty 

 Town. 



