Plate XV.
FOUNDATION-PIT, OR EXCAVATED SITE OF THE LIGHT-HOUSE.
FOUNDATION PIT OF THE LIGHTHOUSE.
Drawn by J. Slight.
Engd. by W. H. Lizars
PLATE XV.
Pl. XV.
Fig. 1. is a Plan of the site of the Light-house, and of the ground or imperfect course, in readiness for receiving the first entire course of the building, represented in [Plate XIII.] Fig. 1. The dark shaded figures delineated upon the Plan in Plate XV. represent the stones of the ground-course, consisting of 18 detached pieces, which vary in their forms according to certain irregular holes in the Rock. From the same cause, the stones of this imperfect course vary in thickness from 6 to 18 inches. The situation of the Foundation-stone will be seen from its having the year of our Lord 1808 cut upon it, as noticed at page [237]. The four exterior stones, which are cut somewhat of a dove-tail form, are of a lighter shade being granite, while the 14 interior pieces, being of sandstone, are of a darker shade. The dark shading on the northern side of the Plan represents merely the shadow of the higher parts of the Rock round the excavated site of the Light-house.
Fig. 2. is a Section of the Foundation-pit, upon the line A B, varying in depth from 18 inches to 5 feet, representing also the dip or inclination of the strata; while the dotted lines above show the form of the lower part of the Light-house.