ANDERSON ON THE TILESTONES OF FORFARSHIRE. 



149 



our fossils and those of the " Upper Ludlow Tilestones," if, indeed, 

 thej are not identical Hugh Miller, in his classic work, the Old 

 Eed 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 far 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 gi'aptolite or other characteristic Silurian 

 organism will reward the researches of the geologist along the flanks 

 of the Grampians. 



ON THE TILESTOXES OF FORFARSHIRE. 



By John 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 palseontologically, 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 Forfarshire, 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 



