209] W. B. Clark 11 



value than to provide means for the shrewd business man who 

 may employ its results to acquire a few more dollars. It is my 

 belief that if the work of a Geological Survey is properly done, 

 with one regard to the solving of the scientific problems as 

 they arise, it will indirectly do the commercial interests of the 

 community a greater service in the end than if the practical 

 aspects of the work are given first place. It would not be diffi- 

 cult to demonstrate this in the case of our Geological Surveys 

 if I had the time. 



Maryland possesses three provinces : first the Coastal Plain 

 which consists of the low-lying country extending from the 

 ocean front to a line drawn through Elkton, Havre de Grace, 

 Baltimore, Laurel, and Washington, which consists of nearly 

 unaltered sediments of relatively simple structure, the basal 

 members of which date well back in geological time, in fact, 

 before the Eocky Mountains or the Alps were formed. They 

 afford a series of problems of great interest but quite different 

 from those of the other areas. 



Lying to the west of the landward border of the Coastal 

 Plain and extending to the base of the Catoctin Mountain is 

 a second area known as the Piedmont Plateau consisting of 

 highly metamorphosed crystalline rocks cut by intrusive and 

 extrusive eruptive rocks, the whole subjected to extensive 

 deformation with intricate folds and faults. The rocks are 

 very old and probably comprise the southern extension of the 

 great Canadian shield, the oldest portion of the North Ameri- 

 can continent. Here are problems of great interest to be 

 solved. 



Beyond and extending to the western limits of the State is 

 a third area known as the Appalachian Eegion that contains a 

 great thickness of deposits lying in large part intermediate in 

 position both as regards age and structure between those of the 

 Coastal Plain and the Piedmont Plateau. Along their east- 

 ern margin they are metamorphosed, folded, and faulted with 

 a large admixture of eruptive rocks that become progressively 

 less complicated westward. In this district still other prob- 

 lems are presented. 



