436 FF. D. Chester—Stratified Drift in Delaware. 
all the Devonian fauna of Iowa as well, leaves the question of 
exact equivalency still doubtful. 
ing for the Kinderhook beds of Iowa and Iilinois,* it 
the Crinoids, the representatives of the Productide, and other 
groups of fossils, all assume Carboniferous features which ally 
the Kinderhook with the Burlington and other undoubted Sub- 
carboniferous strata. 
Art. XLVI.— Observations upon Stratified Drift in Delaware; 
by F. D. CHESTER. 
Ir a line should be drawn from the city of Wilmington to 
the village of Newark until it touched the Maryland boundary 
line, it would follow approximately the southern limit of the 
rchzan rocks of the State. These gneissic and schistose strata 
strike in the common northeast and southwest direction and 
dip at high angles to the southeast. Resting upon the south- 
ern flanks of the latter rocks, occur unconformable Cretaceous 
strata, whose subdivisions and positions exactly correspond to 
those of the New Jersey series. The dip of these latter Creta- 
ceous clays, sand and marls is so small that the surface of the 
country is extremely level. The Archean region, on the 
contrary, is one mass of hills, separated not by wide but by 
extremely narrow valleys, and generally by mere hollows, 
depressions or ravines. ; 
xaminations throughout this hilly country point distinctly 
to the fact that these elevations and depressions have_ 
carved out by the forces of erosion—these forces being ordinary 
aerial disintegration of the gneissic and schistose rocks, an 
erosion along drainage lines. 
That mere hollows entirely surrounded by hills could have 
been dug out only by aerial disintegration is certain. e 
enclosed hollows serve to separate the majority of all the eleva- 
tions of this Archean region. Often hollows connect hollows 
by short passages, the hills sloping in all cases gradually. 
Often, again, hill-slope will meet hill-slope, while the ravine 
separating winds along for distances varyin m a few haa: > | 
dred feet to several miles. Still oftener it is seen that hill 
*Some authors still regard the Goniatite beds of Rockford, Indiana, as Po 
sibly Devonian. ee 
B 
