NOTES AND QUERIES, 
385 
• • New Fossil Locality of Mollusca in the Scottish Old Red. — The 
new deposit of fossil organic remains in the Old Red Sandstone at Dron, as 
noticed by me in the last " Geologist," becomes, upon further examination, 
of the greatest interest as well as theoretic importance in a scientific point of 
view. I shall, therefore, in a few details give the substance of the discovery, 
showing the general bearings, relations, and character of the rocks in the dis- 
trict, and furnishing materials, whether of controversy or agreement, for future 
investigation among geologists. 
The district in question occupies a central position in Strathearn, skiiting 
the Ochils on the south, and trending northerly towards the hill of Moncreiffe, 
which forms an outlier of the Sidlaws. The intermediate space of nearly three 
miles in breadth, is filled with deep alluvial clays, peat, and gravels, and forms 
an extension of the Carse of Gowrie deposits intersected by the river Tay. 
An elevated ridge occui-s at Dron, near the church, which rises steeply towards 
the west ; it is about a mile in length, termhiating in the red sandstone quarries 
of Pitkeathly, and separated by a deep hollow from the Ochil range of trap- 
porphyry. The outcrop of the new fossil beds is on the slope to the south of 
this hollow, forming an insulated little basin of blue marly clays, interlaminated 
with hard micaceous flagstones, and showing all round indications of great 
denudation. 
Extending the view eastward, the basin-estuary of the Tay opens up widely, 
enclosing the various members of the Old Red Sandstone series — the con- 
glomerate of Glenferg, the yellow-spotted beds of Abernethy, the corustone of 
Clunie and Xewbigh, the tilestones of Parkhill, and all of which have their 
correspondents at Clashbennie, Meurie, Inchture, Balruddery, Tealiug, Carmy- 
lie, and Forfar. The intermediate space westerly, from the Ochils to the Gram- 
pians, averaging fifteen to twenty miles in breadth, is occupied with the lower 
Devonian series, embracing all the rich fossiliferous rocks of Forfarshire, the 
deep-red beds towards Birnam, Crief, Donne, and Dumblane ; and which, in 
•some of the members near Gleneagles and Dalmyatt, contain specimens of 
Farka decipiens, Pteraspis, and Cephalaspis. The outgoing of the whole, east 
and west, from the terminating shores of Arbroath and Montrose, being the 
environs of Lochlomond and Dumbarton. 
The relation of every one of the above series of rocks, forming one geo- 
logical group, may be traced in the vicinity of Dron in juxta position each to 
each in an easy forenoon walk. The depth of the deposit, as exposed at the 
mill-dam, varies from twenty to thirty feet. The newly-discovered fossil-bed 
— so attractive yet to be to sciAce — forms the centre-point which underlies 
the whole. It stretches along the narrow ravine to the foot of the Ochils, 
where it becomes enclosed among the trap-porphyries, and where a fine water- 
the series is not now observable, being covered up by the improvements of 
modem husbandry ; but it has been long known as existing, in situ, in the 
neighbouring fields. A few hundred yards distant the quarries of Pitkeathly 
— the Ilolopti/chian red— shows the position of these beds. And, last of all, 
an insulated section of what I regard as the Dura Den i/ellow sandstone, and 
ferruginous marls, c^o^vns all the underlying strata ; it is exposed to the depth 
of thirty to forty feet in the woods of Wester-Dron farm, and the nearest con- 
tinuation of which is ten miles off, at Glenvale, on the Lomonds. When 
fossils M'ere not sought after, or formed no attraction to the curious, these 
upper rocks have been extensively worked, and all their ganoid treasures, if 
ever exhumed, lost to science. 
The oi'f/anic remains just discovered in the lower grey sandstone of the series 
consist of shells and microscopic Crustacea, and are, so far as I am aware, tlie 
first specimens of conchifera yet detected in any of our Scottish Devonian 
The " corustone" of 
VOL. IV. 
2 s 
