1888] MARYLAND ACADEMY OF SCIENCES. 11 



OBSERYATIOS ON THE EOCENE TERTIARY AND ITS 



CRETACEOUS ASSOCIATES IN THE STATE OF 



MARYLAND. 



By p. R. UHLER. 



[Rea<l November 25, 1888.] 



The State of Maryland is richly endowed with the remains 

 of past geological ages. Outside and eastw^ard of her mountain 

 chains and rocky hills rest vast deposits of sedimentary materials, 

 sands, clays and earthy mixtures, the lower members of which 

 extend away off beneath the ocean for more than a hundred miles, 

 if indeed they do not connect with similar formations on the 

 coasts of Europe. These broad sheets of earthy material have 

 been derived from the hard and crystalline rocks which consti- 

 tute the body of the country farther inland. The Piedmont 

 region, lying between the sedimentary Atlantic coastal plain 

 and the Catoctin mountain range, is built of granites, syenites, 

 gneiss, serpentine, mica schists, limestones, and quartzites in 

 great variety. The shattered and displaced parts of these rocks 

 have been successively carried away from their original nplands 

 into depressed levels covered by the waters, and the distribu- 

 tion of their particles has bnilt many types of strata and beds 

 belonging to the Maryland portion of the great coast belt. 

 Slates and felspathic rocks have been ground up by moving 

 waters in rivers, bays and estuaries of the oceanic border, and 

 deep beds of fine mud, later converted into compact clays by 

 uplift above the tide level, have been amassed along the whole 

 eastern side of the State: — clays of Jurassic age and their asso- 

 ciated sands now stretch from the broken border of the Archaean 

 rocks tideward over a width of twenty miles. On the outward 

 margin of those strata, the great Cretaceous marl system as 

 recognized in New Jersey, lies piled up in thick beds and strata 

 which spread farther southeastward in a continuous series. 

 The inner limits of this Cretaceous formation begin in Cecil 

 county, a short distance south of Elkton, extend down the 

 shores of Elk river, pass across the neck of land leading to the 

 Sassafras river, from thence to Wharton Creek, where the beds 

 are in part hid by Quaternary sands, and then farther south 



VOL. I. DEC. 19, 18S8. 



