687 
of Edinburgh, Session 1871 - 72 , 
related by him suggest some questions of considerable importance. 
He has had the kindness to send chips of all the stones specified 
by him. Mr Herdman describes them as, in his opinion, a black 
coloured trap. But they appear to be all bits of micaceous schist. 
The prevailing rock in the parish of Rattray is a coarse red sand¬ 
stone—probably Old Red Sandstone, containing thick beds of coarse 
conglomerate. 
The nearest rocks of micaceous schist are in the hills to the 
north and west. How far off they are it is not stated, nor how 
much higher in level than Rattray parish. But it is pretty evi¬ 
dent that all these boulders came from the hills, and by natural 
agency of some kind. The stone of Glenballoch, weighing as it 
does 25 tons, must have come in that way; and it is almost certain 
that it now occupies the spot and position on which it was 
originally placed. The other stones specified by Mr Herdman 
probably do not now occupy their original site and position, as 
they seem to have been set up for the purposes—whatever these 
were—for which they were wanted. Probably the group of stones 
near the top of Hatton Hill are in their original position, for 
they do not seem to be artificially arranged ; and, moreover, it is 
not uncommon to find boulders in heaps near the tops of hills, 
as if these hills had somehow obstructed the farther progress of 
the agent (whatever that was), which transported the boulders, 
and caused it to discharge its cargo on or near the top of the 
hill. 
Assuming, then, that the stone of Glenballoch is an erratic from 
some northern or westerly point, one question would be, What 
caused the transporting agent to drop it at the place where it 
now stands? Why should it not have been carried farther? Per¬ 
haps an examination of the country might suggest data to aid in 
the solution of this question. 
The position of the boulder and its attitude appear to deserve 
attention, provided it can be correctly assumed that they were 
received by natural and not by human agency. 
Mr Herdman states that the boulder stands in a field which slopes 
pretty rapidly down towards a stream, running through a narrow 
glen. This field seems to form one side of that glen, or small 
valley, through which, he says, there was formerly a pass much 
