272 
GEOLOGY OF THE FIRST DISTRICT. 
pervious sands and gravel, and the springs flow from about tide-water level, or a few feet 
above, and are very uniformly distributed along the coast. The sides of these valleys are 
almost all gravelly and pebbly, and the bottoms the same; except that in the hilly ranges, 
they are frequently loam or clay, covered by superficial beds of sand and gravel. 
Disturbance of the strata since their deposition. 
Few examples have been observed of disturbance of the strata under consideration, that 
cannot be accounted for by the action of alluvial causes, as slides, and the wrinkling of strata 
produced by the lateral pressure of slides. Fig. 12, Plate 4, may, like fig. 9, be attributed 
to a recent slip producing a fault. In figs. 4, 5, 6, 7 and 11, the period of disturbance must 
have preceded the period of the deposition of the drift deposits, for the disturbed strata seem 
to have been denuded previous to the deposition of the unconformable strata. Figs. 4, 5, 6, 
11 and 15 might be attributed to the effects of slips, and the lateral force of slips, between 
the period of their deposition and that of the drift; and figs. 4, 5, 6, 7 and 15, to the period 
before the deposition of the blue clay with iron crusts, which preceded the drift epoch. Fig. 
7 seems to be the result of a force acting from below, or a lateral force on a larger scale than 
that affecting the others, and at the same period as the last. 
At the localities of figs. 10, 13 and 16, no data are afforded to estimate whether the distur¬ 
bance was at the same time as the preceding ; but the strata show that it was daring the same 
epoch, between the deposition of similar strata. The disturbance indicated on fig. 8 was 
probably effected at the same period as that of figs. 4, 5, 6, 7 and 16, as the same strata 
are affected, and the locality is near those of the figures last mentioned. 
CONSIDERATION OF THE EaUIVALENCY, AND OF THE PHYSICAL CAUSES 
OF THIS FORMATION. 
1. Equivalency of the Long-island Division. 
It will be seen by referring to what precedes, 
1. That the white, red, mottled, brown and blue clays, and variegated and some other 
sands of Long and Staten islands, are similar in their general characters, ^nd in their mineral 
and fossil contents, to certain beds of clays and sands in New-Jersey, and are undoubtedly a 
continuation of the same formation. 
2. Those beds referred to in New-Jersey, have been shown by Dr. Morton, Professor 
H. D. Rodgers, my own observations and those of others, to belong to the lower part of the 
cretaceous and greensand formation of New-Jersey, and to underlie the marl deposits of that 
formation. 
3. That some of the sands, loams and clays of Long island, contain a green earthy material 
and green granules, like some of the beds of the New-Jersey marls, though in comparatively 
small quantities. 
