They occur generally in pockets within five feat from the surface, but they can hardly be called included minerals, as they are rather, as their mention suggests, pockets, and adjacent or in contact with the intruded granite or metamorphosed rock joining the formation at this point. This is seemingly at variance when we consider datholite, but when we do find it in pockets a hundred and fifty feet below the surface, in the Weehawken tunnel, it is not in the trap, but on the surface of what was a cleft or empty vein, since filled up with chlorite extending from the surface down, while natrolite, etc., by the trap having clefts of such variable and often great depth, allowed the solution of the portion thus contributed that infiltered from the surface easy access to the beds in which they lie, the mode of access being since filled with densely packed calcite, which was present in over-abundance. This is not applicable to serpentine, as the clefts are never of any great depth, and the five feet before mentioned are a proportionately great depth from the surface. As I mentioned in commencing this paper (Part I), every part of the success of a trip lies in knowing where to find the minerals sought; and by close observation of these relations much more direction may be obtained than by my trying to describe the exact point in a locality where I have obtained them or seen them. There is much more satisfaction in finding rich pockets independently of direction, and by close observance of indications rather than chance, or by having them pointed out; for the one that reads this, and goes ahead of you to the spot, and either destroys the remainder by promiscuous cuttings, or carries them off in bulk, as there are many who go to a locality, and what they cannot carry off they destroy, give you a disappointment in finding nothing; consequently, I have considered that this digression from our subject in detail was pardonable, that one may be independent of the stated parts of the locality, and not too confidently rely on them, as I am sometimes disappointed myself in localities and pockets that I discover in spare time by finding that some one has been there between times, and carried off the remainder. The characteristics of magnesite I have detailed under that head under Pavilion Hill, Staten Island; but it may be well to repeat them briefly here. Form as above described, from a white to darker dirty color. Specific gravity, 2.8-3; hardness, about 3.5. Before the blowpipe it is infusible, _and not reduced to quicklime_, which distinguishes it from dolomite, which it frequently resembles in the latter's massive form, common here in veins. It dissolves in acid readily with but little effervescence, which little, however, distinguishes it from brucite, which it sometimes resembles and which has a much lower-specific gravity when pure.