1888] MARYLAND ACADEMY OF SCIENCES. 17 



Where the thin ends of the black marl strata run lengthened 

 out over the lower slope of the Albirupian coast, a mass of 

 macerated twigs, leaves, buds, scales, barks and bits of numer- 

 ous kinds of plants and trees lie packed together in hopeless 

 confusion. Early in this period, before the filthy black muds 

 had accumulated in thick beds and when the glauconitic sands 

 were but beginning to be thrown down into the quiet basins, a 

 period of repose allowed the fine white sands to accumulate 

 steadily upon the level beds of the clean swamps and scarcely 

 stained channels. Upon these, at frequent intervals, deposits 

 of aluminous clays, washed from the adjacent Albirupian strata, 

 were spread out in thin layers, binding the sands together in 

 slender bands, and securing therein the numerous leaves, twigs 

 and other fragments of plants and trees which were settling 

 gently down into the shallow waters. Following that stage 

 came one of restless movement of waters, in which coarse sand 

 and a small proportion of gravel were laid down against the 

 sandy slopes beneath the waves. Energetic erosion scooped out 

 hollows in places along the submerged shores of the Laminated 

 Sand belt, and gradually the black mud charged with the 

 decaying remains of plants and trees was raised into high piles, 

 the moundlike forms of which still present bold reliefs in the 

 cliffs which have been cut by the rivers cited, on both shores 

 of Chesapeake Bay. As the cliffs are ascended the green sand 

 becomes more abundant, loses its black or dull bluish color, is 

 more stained by ferruginous matter, and where the country 

 rises stage after stage, the upper surface of -each hill becomes 

 more hydrated and changed to a rusty brown sand. On the 

 less denuded ridges, which rise to an altitude of more than one 

 hundred feet above tide, the grayish drier, and purer greensand 

 rests in variable strata upon the latter, increasing the thickness 

 to nearly one hundred and fifty feet. Such is the case at and 

 below Mount Misery, on Round Bay, where may be seen a 

 section of almost all the beds, from the Laminated Sands up to 

 the ferruginous depauperated sands of the Eocene formation. 

 Ascending from the bed of the Severn river, we rise to the 

 summit level of the country by two or three stages, representing 

 apparently different periods of denudation. At the bottom of 



