ANDERSON — ON THE TILESTONES OF FORPARSHIBB. 
149 
our fossils and those of the " Upper Ludlow Tilestones," if, indeed, 
they are not identical. Hugh Miller, in his classic work, the " Old 
Bed Sandstone," assigned our Forfarshire strata to a middle formation 
of the Old Red or Devonian system. Murchison, on the other hand, 
places our " Cephalaspis-beds " at the base of the system ; and the 
fossil evidence which I have briefly related seems to decide in favour 
of the latter view. This point is of great value in the arrangement 
of our rocks, as in the grits and conglomerates, and even in the 
underlying and highly metamorphosed slate-rocks, we are to recognise 
the equivalents of the Silurian system as known in the south of 
Scotland, or better still in Shropshire and Wales. 
So fixr as I know, no fossil has been disentombed in this part of 
the country from any strata beneath the flagstones ; but perhaps the 
discovery, some day, of a graptolite or other characteristic Silurian 
organism will reward the researches of the geologist along the flanks 
of the Grampians. 
ON THE TILESTONES OF FORFARSHIRE. 
By JofiN Anderson, D.D., F.G.S., etc. 
The March number of The Geologist contains, I observe, a notice 
of the " Upper Ludlow Tilestones," and the author invites descriptions 
of their equivalent beds in other districts. Now, so close are the 
resemblances, lithologically and palteontologically, between these de- 
posits and those of Forfarshire, that they may be regarded as part of 
one and the same series. I have been induced, therefore, to throw 
together the following observations upon our northern Scottish 
system. 
The rocks to which I refer occupy a narrow but extended trough- 
line along the central district* of Forfirshire, commencing on the east 
near Montrose, and terminating at Babruddery and Rossie Den on the 
west. They trend in a south-westerly direction, across the river Tay, 
into Fifeshire at Parkhill, Newburgh, and along the northern slope of 
