THE GEOLOGY OF SOUTH-EASTERN KINCARDINESHIRE. 931 
subangular fragments of the underlying rocks, but they contain also rounded pebbles 
of weathered granite and schists. The purple sandstones overlying the basement 
beds appear to consist mainly of finely comminuted debris of the rocks of the Upper 
Cambrian series. 
Next in the succession comes a thick series of grey and brown ochreous sandstones 
with intercalations of pale red mudstones. The sandstones often contain much volcanic 
debris in the form of fragments of andesitic and felsitic rocks; clay galls, indicating 
contemporaneous erosion of clay beds, are abundant ; and false-bedding is everywhere of 
common occurrence. Beautiful examples of sun-cracks have been noted in the mud- 
stones. On the south side of the entrance to Cowie harbour a dip fault with down- 
throw to the south shifts the above series to the west, and on the foreshore between 
Cowie and Stonehaven Bay the brown and grey ochreous sandstones are overlain by a 
coarse volcanic conglomerate associated with a belt of tuffs and tuffaceous sandstones. 
The volcanic conglomerate has a maximum thickness of about 30 feet, and may be 
traced as a conspicuous ridge on the foreshore extending in a south-south-westerly 
direction from Cowie pier. As it approaches the Cowie harbour fault it is traversed by 
a large number of small dip faults, each of which shifts the outcrop slightly to the east- 
ward as the conglomerate is followed towards Cowie. Made up almost entirely of 
rounded boulders of hornblende andesites and rhyolites, the conglomerate is overlain by 
a belt of soft red andesitic tuffs with a maximum thickness of 27 feet, to which succeeds 
a thin bed of fine conglomerate with green tuffaceous matrix. 
The next member in the succession is a massive red sandstone with occasional thin 
mudstone intercalations. It presents no feature of particular interest. 
The red sandstone is overlain by about 600 feet of grey sandstone and sandy 
shales with green and grey mudstones. ‘This group (No. 6) is the most important in 
the series, since, alike in its lithological characters and in its fossil contents, it shows 
the Silurian rather than Old Red Sandstone affinity of the succession. The predomi- 
nant sediments are grey sandstones, occasionally rich in clay galls, and in places 
containing bands of calcareous nodules. At intervals there occur intercalations of 
green and grey sandy mudstones and shales, in which Dictyocaris is found in great 
abundance. The most noteworthy of the mudstone and shale groups occurs about 
20 yards east of Cowie harbour. On visiting this section in August 1909, in company 
with Dr Peacw and Dr W. T. Gorpon, we found not only Dictyocaris, but also 
Eurypterus sp. and fragmentary plant remains, and ina thin bed of reddish sandy 
mudstone, overlying the red sandstone (No. 5), Dr Gorpon discovered several fish 
plates. Some of the fish fragments were suggestive of Birkenia. Dr Gorpon and 
Dr Peracu joined me again during the following summer in order that we might 
try to get material sufficient to establish the horizon of this fish eee and considerable 
additions were made to the finds of the previous year. 
The fishes were submitted to the late Dr R. H. Traquair, who undertook the 
description of new species. In a preliminary note contributed to the Geological 
TRANS. ROY. SOC. EDIN., VOL. XLVIII. PART IV. (NO. 34). 138 
