_Situation and Dimensions._ [Sidenote: Situation.] The Bell Rock may be described as a most dangerous sunken reef, situate on the northern side of the entrance of the great estuary or arm of the sea called the Firth of Forth; and as such directly affecting the safety of all vessels entering the Firth of Tay. Its position, as will be seen from the Charts, Nos. 3. and 4., which accompany this work, is in west longitude from Greenwich 2° 22´, and in north latitude 56° 29´. From St Abb’s Head in Berwickshire, it bears north by east per compass, (variation 27° 20´ west in the year 1819), and is distant about 30 miles; from the Island of May north-east 17 miles; and from the promontory or cape called the Redhead, in Forfarshire, it bears south-west, and is distant 14 miles. But in easterly directions no land intervenes between the Bell Rock and the coasts of Norway, Denmark, Germany and Holland. [Sidenote: Dimensions.] The dimensions of the north-eastern or higher compartment of the Rock where the light-house is built, are about 427 feet in length, and 230 feet in breadth. Besides these dimensions, the south-western reef extends about 1000 feet from the main rock. The greatest length, therefore, of the Bell Rock, which may be said to be dangerous to shipping, is about 1427 feet, and its greatest breadth is about 300 feet; but the outline or margin of the Rock is quite irregular, as will be seen from the Plates marked Nos. 5. and 6. _Natural History._ [Sidenote: Mineralogy.] The Bell Rock consists of sandstone of a reddish colour, which in some places contains whitish and greenish spots of circular and oval forms, irregularly interspersed through the rock. It is of a fine granular texture, containing minute specks of mica. It is very hard, and, in the language of the artificer, is tough, and rather difficult to work; and in some parts it is found to rise in masses having a conchoidal fracture. Its angle of inclination with the horizon is about 15 degrees, dipping towards the south-east. The strata are thick and unequal, strongly cemented together, and running in the direction of north-east and south-west. The surface of the Rock is rugged, and full of cavities, so that walking upon it becomes rather difficult. A longitudinal section of the Bell Rock, taken in a north-easterly and south-westerly direction, may be described as consisting of a higher and a lower level. The cross section, taken in a south-easterly and north-westerly direction, exhibits the abrupt and pointed terminations of the strata, though it appears level when seen from a distance. [Sidenote: Wasting effects of the Sea.] [Sidenote: Natural History.]