IIS 
At present it is one of the oldest, most fashionable, and most 
exclusive districts in town, and covered with well kept lawns 
which prevent careful observation. ‘Thus was its location lost. 
Nevertheless to one constantly on the field to take advantage of 
small excavations, as the removal of trees and the transplanting 
of flowerbeds, finding the direction of the dike is not at all diffi- 
cult. That it was not a horizontal sheet was further evidenced by 
a quotation from William’s paper “ An excavation fifty feet fur- 
ther up the hillside did not pass through it at all.” 
I have traced dike No. 4 northward from Green street across 
James street to Highland Place, beyond which it is entirely lost. 
South of Green street it was noticed about sixty feet. The entire 
distance over which it has been noticed is more than a quarter of 
a mile. As plotted on the city map the strike is N. 14 degrees EF. 
A great anticlinal fold, produced by the igneous matter forcing 
its way through the horizontal rock, was especially noticable in 
the trench on account of the existence there of a heavy limestone 
band among the thinner shales. The same thing, though less 
noticable, can be seen in the thinner bedded shales of the perma- 
nent exposure. 
THE DEWITT DIKE. 
Until some two weeks ago, I had secured but few additional 
facts concerning the relations of this dike, outside of those con- 
tained in Dorton’s paper.* 
An exposure on the southern side of the hill, 250 feet south- 
west of the reservoir, seemed to indicate the direction of the dike 
but in the absence of other evidences in this direction this could 
hardly be taken as conclusive evidence of its strike. It is also 
safe to say that the slight disturbance 600 yards north of the res- 
ervoir mentioned in that paper, together with another in the field 
a quarter of a mile farther north, have no connection with the 
dike but were produced by the action of salts whose presence in 
the partially hardened layers produced a wrinkling of the same. 
Quite recently, however, I have found the extension of the dike to 
*American Journal Science, Vol. XLIX, June, 1895, 
