The geological structure of the neighbourhood of Stonehaven being rather peculiar, we are induced to give the following account of it, for the information and guidance of geologists who may happen to visit the place.

Stonehaven is situated at the north eastern extremity of the great " Old Red Sandstone " field of Scotland, which rests on the southern Flank of the Grampians, extending as far westward as the Firth of Clyde, and spreading over a large portion of the counties of Kincardine, Forfar, and Fife, in which last it is seen dipping under the Coal Measures. To the northward of the Grampian range, the old Red Sandstone is only to be met with in detached pieces, at Aberdeen, Gamrie, in Banffshire, and in the district of Strathspey, until we arrive at the northern shore of the Moray Firth, when it is again seen skirting the counties of Cromarty, Ross, Sutherland, and Caithness. It also appears in numerous isolated patches through Ross and Sutherland, crowning the tops of the highest mountains, naturally leading to the conclusion, that ere the lofty granite and gneiss mountains which now occupy the Highlands had been upraised, Scotland was covered with continuous beds of Red Sandstone, these mountains having, in the course of their upheaval, so broken the sandstone beds, as to lead to their denudation by succeeding floods, which have evidently swept, at an unknown period, over the island.

Along the shore, to the northward and southward of Stonehaven, a fine and interesting section of the various rocks which girdle that bold and striking coast may be seen. At what is commonly called the "Paint Heugh," a ferruginous clay rock, a little to the north of the Old Kirk of Cowie, the Old Red Sandstone is to be seen resting at an angle of not less than 80 Deg., dipping to the S.E., and on the north or opposite side of that rock, the Chlorite Slate is to be seen dipping to the N.W., at a similar angle, suggesting the idea that the iron rock is the edge of the wedge, by which the beds of Sandstone and Chlorite Slate have been tilted up into their present remarkable and unnatural position. The Chlorite Slate is known to extend across the Island in a south-westerly direction, as mentioned by Dr. Jameson, to Cowal in Argyleshire. In the neighbourhood we have been describing it contains a bed of induratted talc, and numerous veins of carbonate of lime and quarte. It rests on gneiss rocks of great thickness, which last in turn rest on the granite or a Syenite rocks that skirt the northern side of the county.

The Old Red Sandstone, from where it is first seen at the point described, southward to Downie, is a sandstone of various degrees of hardness and shades of cooler from red to greenish; and several beds, especially at the "Red Craig", the quarry directly to the south of the harbour of Stonehaven, are found to answer well for building purposes. These beds are all nearly vertical, and cannot be estimated at less than 4,000 feet in thickness. At Downie the conglomerate begins, and continues to be the prevailing rock for several miles along the coast. From where it commences, to a little beyond the Castle of Dunnottar, the conglomerate has a vertical position. It soon after loses this, and by the time it has reached the south-side of Thorny-hive it has changed its dip from S.E. to a small inclination to the s.w. The vertical beds of conglomerate may be estimated at about the same thickness as the preceding beds of sandstone, making in all the enormous thickness of not less than 8,000 feet, and eliciting the wonder of the beholder when he contemplates the vastness of the power required to raise so enormous a mass, from a horizontal to its present vertical position. In none of these beds have organic remains been found, although these are to be met with in the county, in micacious sandstones or flag beds near CanterLand, which contain numerous prints of what appear to have been grasses, with their fructification. It is not likely, however, from the nature of the rocks in the immediate neighbourhood of Stonehaven, that such remains will be found.

In the portion of the county occupied by the Old Red Sandstone, there are numerous and evident marks of volcanic agency, and trap and porphyritic rocks abound. A little to the north of the harbour of Cowie, a remarkable dyke of claystone porphyry is to be seen, running from east to west, and intersecting the beds of Sandstone which appear to have been indurated by its heat, which is also the case with the sandstone which is in the immediate vicinity of the ferruginous rock already alluded to. There is also another remarkable rock, near the Red Craig, attributable to volcanic origin ; a very hard red claystone. Besides these, there are numerous masses of porphyry and trap to be met with at Uras, Slains, and the Knock Hill, in the parish of Glenbervie. In fact there is scarcely an eminence in the district alluded to that does not owe its origin to the same agency, and on examination will be found to contain beds of these rocks.

Along the shore numerous caves are to be met with, inhabited by flocks of rock pigeons ; the most remarkable of which is one named from its great length, the Long Gallery, about a mile and a half south from Stonehaven. It enters the perpendicular face of the rock, which is here about one hundred and fifty feet high, by an aperture about forty feet high and thirty wide, gradually narrowing to the other end, where it also comes out in the face of the rock. It can be passed through its whole length, which is about two hundred yards, by a boat at low water; which thus goes in at one aperture in the front of the precipice, and comes out at another; being enveloped in total darkness in the middle.

Further southward, and about three miles from Stonehaven, is a remarkable rock of the conglomerate or plumb-pudding species, called Fowl's Heugh, about a mile long, and two hundred feet high, quite perpendicular, and in some places overhanging, often visited by sportsmen on account of the innumerable sea fowl, of the kittiwake gull species, which resort to it in the breeding season ; finding convenient places for depositing their eggs in the recesses formed by the vacant beds of pebbles, which time and accident have abstracted. It is generally let to a tacksman, who plies his fearful calling in pursuit of the young birds by descending the precipice, by a rope, dangling in mid air, with twelve fathoms water below him, in the manner practised at St. Kilda.

It is farther noted for being the breeding place of that noblest of birds of prey, the peregrine falcon; of which, each season, a single pair have their nest in the rock, and never more; in accordance with the maxim adopted by these birds, " to suffer no brother near their throne ; " and if one of the pair happens, any one year, to be killed, it is observed that its place never fails to be supplied next year.