Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/205

 pyramids; some are of the highest lustre and transparency, others variously coloured by iron ore, or containing acicular crystals of that substance, or of manganese; some are said to be pierced with needles of sulphate of strontian.

Behind Brandon Hill there are beds of sand highly impregnated with iron, and containing impressions both of shells and vegetables. In the descent on the south of Brandon Hill some singular masses of breccia project from the ground, containing rich iron ore, and assuming nearly a cubical form. The siliceous iron-stone of Brandon Hill has been found to make the best grinding stone for enamel colours. Below the siliceous iron-stone, upon the banks of the river near the Hot-well House, three small beds of coal make their appearance. These have been worked close to the river on its southern bank: and on the northern at the distance of two miles, near the Fort, a trial for coal was made some years since, but the seams found were not worth working.

Upon the banks of the Avon, immediately below the coal, there is found an extensive series of beds consisting principally of limestone, which form that high ridge of land which has been already noticed. This ridge passes on the north to Almonsbury and Alveston, and on the south to Clevedon, where the coal field of Nailsea begins. These beds upon the banks of the Avon are remarkably regular in their stratification, being all nearly parallel to one another and dipping to the north-west at an angle of about 45°. They are better observed on the northern than on the opposite bank, being on the former very much exposed by the operations of the quarrier.

Upon the top of this ridge and upon the fractured edges of the limestone strata, behind Clifton, there has been a partial deposition