THE GEOLOGY OF SOUTH-EASTERN KINCARDINESHIRE. 955 
XIII. Upper Otp Rep SanpstTone. 
A narrow interrupted belt along the coast in the neighbourhood of St Cyrus is 
occupied by rocks which, in their lithological characters, are markedly different from 
the Lower Old Red Sandstone. No fossils have been recorded from these beds. In 
the Geological Survey map they are assigned to the Upper Old Red Sandstones, and 
recent work has fully confirmed this view. As Dr Hickiinc* has pointed out, the 
lithological and stratigraphical evidence together show conclusively that the isolated 
patches at St Cyrus, Buddon Point, and Arbroath must be regarded as outliers of 
the extensive tracts of Upper Old Red Sandstone of the Carse of Gowrie and the 
north of Fife. 
The St Cyrus outlier consists of two separated areas—one extending from Rock Hall 
fishing station to East Mathers, the other from Kirkside to the mouth of the North Esk. 
In each case, but particularly in the southern tract, the solid geology is to a very large 
extent obscured, partly by raised beaches and blown sand, partly by boulder clay. 
The rocks of the Rock Hall and East Mathers area include cornstones, calcareous 
sandstones, bright red marls, and red false-bedded sandstones and grits—an association 
of sediments of frequent occurrence in the Scottish Upper Old Red Sandstone. The 
dip of the beds is always low, and the total thickness of strata exposed cannot be 
very great. At Arbroath, as has been shown by Dr Hickuine, the basement beds 
consist of about 200 feet of conglomerates and sandstones derived chiefly from the 
disintegration of sandstones and conglomerates of Lower Old Red Sandstone age ; 
at Buddon Point there is a good development of the higher, cornstone, type of 
sedimentation. In the St Cyrus outlier the base of the series is nowhere visible, 
since the junction with the older rocks is everywhere a line of faulting and not a 
natural boundary as indicated in the published maps. On the road leading from 
the shore to Milton of Mathers there is exposed a group of bright red sandstones 
and grits, which in all probability underlie the cornstone horizon, and may represent 
part of the Arbroath series. The sandstones contain occasional rounded pebbles, 
and among these I noted a chatter-marked boulder of jasper, derived most likely from 
a conglomerate of the Lower Old Red Sandstone. The cornstone group includes 
typical cornstones, often with a marked development of chert, flesh-coloured sandstones 
with a matrix of crystalline calcite, sandstones with calcareous nodules, soft red marls, 
and red false-bedded sandstones. At Rock Hall the main exposure of cornstone is 
underlain by a bed of conglomerate made up of fragments of limestone, chert, and 
sandstone of types found locally in the Upper Old Red series, and obviously indicative 
of contemporaneous erosion. It is beyond the scope of this paper to give a detailed 
petrographic account of the curious variations in the sediments of the cornstone group, 
but such an investigation would undoubtedly throw valuable light on the conditions 
which prevailed in Upper Old Red Sandstone times. 
* Geol. Mag., dec, 5, vol. v. p. 403. 
TRANS. ROY. SOC. EDIN., VOL. XLVIII. PART IV. (NO. 34). 141 
