26 
THE H^LL. 
The rocks which rise on the hanks of the Avon have been 
-always celebrated for their picturesque character, this feature 
being dependent not only upon their bold outlines, but upon their 
varied colours and irregular forms. Several varieties of orna- 
mental marbles are exhibited from the rocks of this district, 
especially from the limestone of Clifton. Like those already 
described, these marbles are fossiliferous ; crinoids are common, 
dish -palates occur in some, and many of the beds are rich in corals. 
Among the British marbles in Case II. will be found a speci- 
men of the argillaceous limestone commonly called “ Landscape 
marble” in allusion to the peculiar dendritic markings which it 
exhibits. It occurs in the Penarth or Rhyetic beds (p. 153), 
especially in the neighbourhood of Bristol ; and is sometimes 
used, under the name of Gotham marble, for the manufac- 
ture of small ornaments. The Ammonite marble (No. 17), 
from the Lower Lias of Murston near Yeovil, takes its peculiar 
character from the vast numbers of ammonites which it 
contains ; these fossils, somewhat resembling the shells of the 
living nautilus, will be noticed in another place (p. 145). 
Attention may here be directed to the specimens of conglo- 
merate from Glamorganshire (Nos. 15 and 83), which belongs 
to the New Red Sandstone series, and rests frequently on the 
upturned and denuded edges of the older strata. The fragments 
forming the conglomerate or “ pudding stone ” have been 
derived, to a large extent, from the Carboniferous Limestone, 
and are united by a cement sometimes calcareous, but usually 
magnesio -calcareous or dolomitic. A line slab of this dolomitic 
conglomerate is exhibited from Draycot, near Wells (No. 15). 
With these dolomitic conglomerates may be noticed some speci- 
mens the peculiar breccia -marble of the Isle of Man (No. 22). 
The black marble from the Carboniferous Limestone of the Isle 
of Man has been selected as an appropriate material for the 
pedestal (No. 205) supporting the bust of Professor Edward 
Forbes, who was a native of the island. 
In Case II. will also be found a few other marbles of less 
importance than those already noticed. These are from Somer- 
setshire, Herefordshire, and South Wales. The Carboniferous 
Limestone of the Isle of Anglesey has furnished the black 
marble employed for the columns Nos. 16 and 158. 
At the entrance to the Geological Survey Office is a slab of 
dark brown limestone, rich in corals, from the Yoredale strata 
of Frosterley, near Stanhope, in Vfeardale, Durham (No. 144). 
This marble has been used for columns in Durham Cathedral. 
Irish Marbles. — Pilaster 50. Columns , &c. 41, 67, 73, 
112, 114, 140, and 171. Cubes in Case II. 
Ireland is rich in marbles ; indeed in no other part of the 
British Islands is the Carboniferous Limestone developed on so 
grand a scale. Extending over a great central plain, 120 miles 
