MARYLAND GEOLOGICAL SURVEY 35 



1809 



MACLURE, WM. Observations on the Geology of the United States, 

 explanatory of a Geological Map. (Eead Jan. 20, 1809.) 



Trans. Amer. Phil. Soc., o. s. vol. vi, 1809, pp. 411-428. 

 Broad correlations and generalizations only. 



1814 



MITCHILL, SAML. L. A Sketch of the Scenery in the region around 

 Harper's Ferry where the ridge of the Blue Mountains is penetrated by 

 the joint waters of the Potomac and Shenandoah rivers. In a letter to the 

 editor; dated Harper's Ferry, July 4, 1812. Bruee's Amer. Min. Jour., 

 vol. i, Xew York, 1814. pp. 211-218. 



The author discusses the geology and stratigraphy along the Potomac between Har- 

 per's Ferry and Washington and regards the slates as older than the limestones. 



1817 



MACLURE, WM. Observations on the Geology of the United States of 

 America, with some remarks on the effect produced on the nature and 

 fertility of soils by the decomposition of the different classes of rocks. 

 With 'two plates. 12mo. Phila., 1817. 



(Republished in 1818, Trans. Amer. Phil. Soc., vol. i, n. s., pp. 1-91.) 

 A classic work giving many references to the limits and character of the geologi- 

 cal formations in Maryland. The text and map (120 m. to the inch) represent the 

 Cretaceous extending southwest to the Susquehanna only. All land to the southeast 

 of " Primitive " is " Alluvium " in Maryland. Pages 105-107 deal especially with 

 Maryland. 



1834 



AIKIN, WILLIAM E. A. Some notices of the Geology of the Country 

 between Baltimore and the Ohio River, with a section illustrating the 

 superposition of the rocks. 



Amer. Jour. Sci., vol. xxvi, 1834, pp. 219-232, plate. 



The most complete description of the geology of central and western Maryland 

 published up to the time of its appearance. 



DUCATEL, J. T., and ALEXANDER, J. H. Report on the Projected 

 Survey of the State of Maryland, pursuant to a resolution of the General 

 Assembly. 8vo. 39 pp. and map. Annapolis, 1834. 



Maryland House of Delegates, Dec. Sess., 1833, 8vo., 39 pp. 



Another edition, Annapolis, 1834, 8vo., 58 pp.. and map. 



Another edition, Annapolis, 1834, 8vo., 43 pp., and folded table. 



Amer. Jour. Sci., vol. xxvii, 1835, pp. 1-38. 



