THE MINERALOGY OF SCOTLAND. 447 
stream beds of Scotland. Even after having analysed these sands from several 
localities, I would not speak with much confidence, unless the sand could be 
traced to its rock source. If they lie near to, or on a lower level than an igneous 
rock, they probably are titanic ; if the rock, on the other hand, be granitic, or 
any of the schistose rocks other than chlorite state, they most probably consist 
merely of powdered magnetite. A rock of chlorite schist would yield ilmenite, 
rather in fragments, than in powder. 
While it would be well-nigh endless to enumerate the localities in which I 
have observed “ black sands” of a doubtful nature, I may note my having found 
iserine, in fragmentary-looking masses which have taken a cast of the faces of 
the contiguous minerals, in two classes of rocks. 
First, in a diorite which passes into or assumes the features of syenite; and 
secondly, in the denser varieties of the Tertiary doleritic and basaltic traps. 
In the first named rock, it occurs in very small amount, in the diorite which 
is seen both to the east and to the west of Portsoy. 
It is in quite visible particles or patches, in the easterly belt of that rock 
at Retannach, associated with labradorite, augite, paulite, and pyrrhotite. It 
is seen in fully larger pieces in the giant-crystalled diorite of Glen Bucket. 
Its associates here are hornblende, Biotite, sphene, and labradorite. With 
much the same associates, it is seen south-east of Tullyjuke, at the head of the 
Deskery, and on the north slopes of Morven ;—-the rock here tending more to 
syenite, before it shades off into the granite of Cuilbleen. In granite itself, 
iserine seems to give place to magnetite ; the titanium finding a lodgment in 
the sphenes, which begin to show themselves where diorites shade off into 
syenites ;—which are characteristic of syenites ;—and which also affect the in- 
termediate gradations of syenites into granites. 
The iserine of traps is generally in minute grains. Here, as at localities 
near St. Andrews (Kinkell) and Elie, its associates are saponite, sanidine, 
olivine, and pyrope. 
The largest imbedded particles which I have seen were from the acidic trap 
rock—termed “ syenite”—of Ben Grigg, in Mull. These were shapeless, and 
in parts rusty brown; they were not half the size of a bean. 
Near Tilquilly, and at Badnagauch on the Deskery, in Aberdeenshire, similar- 
sized pieces are imbedded in diorite, along with dark green hornblende, labra 
dorite, Biotite, Allanite, and sphene. 
The difficulty connected with the recognition of iserine may be shown by 
stating, that what I myself collected at the mouth of a stream at Sangoe Bay, 
Durness, Sutherland, as an iron sand, proved after examination to be totally 
non-magnetic, and was probably pulverised black hornblende; and that another 
“black sand” sent me by Mr, ALEXANDER CRUICKSHANK of Aberdeen, as iserine 
from the parish of New Deer, proved after analysis to be pounded schor/, with 
