1879. } The Mesozoic Sandstone of the Atlantic Slope. 291 
The text accompanying diagram, p. 16, is not clear, and there- 
fore cannot be criticised. The conglomerates of Maryland and 
Pennsylvania do seem to mark two horizons near the upper and 
lower parts of the New Red series. 
Another oversight is the assertion that the bold line of bluffs 
composed of crystalline schists can be followed to a distance from 
Stony Point, N. Y., towards Virginia, sufficiently far to account 
for the conglomerate of that edge as its shore deposit. Over long 
stretches of this intervening distance the only high ground is 
made of these coarse and hard beds. 
In the summary of reasons for accepting the theory of unity 
between the New England and New Jersey Mesozoic, considera- 
tions Nos, 3 and 4 seem to be new and valuable. No. 1 is valua- 
ble. No. 2 if true of New Jersey is not so in Pennsylvania, 
where on the very eastern margin of these beds, in York county 
(as on the western), the rock is a conglomerate (See Report C, 
Second Geol. Surv. of Penna., and CC bid, p. 264.. Section 6. 
Frazer). No. 5 on the continuity of elevated ground, if well 
founded from Hudson river to New England, is not so for the 
entire course south-west. 
In the discussion of the eruptive rocks Mr. Russell makes a 
very interesting point in regard to the crescent shape of the out- 
bursts of trap in the New England and New Jersey Trias. In the 
former the horns of the crescents turn eastward, while the con- 
vex side is towards the west, whereas in the New Jersey series 
this order is reversed. 
But it is evident that the trap rocks of New Jersey must differ 
materially from those in Pennsylvania, and also in Connecticut, 
because he states that “ they are usually composed of an intimate 
combination ” (sic) “with some form of feldspar.” They very rarely 
contain any hornblende elsewhere, and in the large collection of 
traps from Pennsylvania there are but one or two, and these from 
exceptional localities in which hornblende has been detected. 
Another difference lies in the fact that it is not difficult to find the 
junction of the trap with the shales and sandstones that underlie 
them. In Pennsylvania this is always difficult and sometimes 
impossible. 
Mr. Russell expresses the same view of the effect of a sinking 
_ Of the floor, or what is the same thing, a rising of the eastern 
margin of the MeSozoic area, as that given in bee. 2d G. S. of Pa, 
Pp. 269 and 271. 
