340 



JURASSIC. 



Base beds are used for building, for columns, sinks, troughs, rollers, etc. Some 

 of the beds are burnt for lime. About the year 1623, in the reign of James I., the 

 Portland stone appears to have first attracted attention. St. Paul's Cathedral, 

 and many of the churches and other large buildings erected in the reign of Queen 

 Anne, were constructed with stone said to be more durable than that now 

 generally employed.^ The stone was then obtained on the margin of the Island, 

 and transported by vessels. London Bridge was also in part constructed from 

 this stone. 



The Portland Rocks form the grand cliffs between Durlston Head and St. 

 Aldhelms or St. Albans Head, also Gad Cliff, and portions of the cliffs east and 

 west of Lulworth Cove, and Durdle Door.^ These cliffs are for the most part 



Fig. 52. — Portland Beds at Anvil Point, Durlston Head, 

 near swanage. 



abrupt and inaccessible, and it may be useful to warn the rambler that he cannot 

 travel along the foot of Gad Cliff to Worbarrow. From Swyre Head (667 feet), 

 east of Kimeridge, a spur of Portland Sand, a most extensive view is to be obtained 

 overlooking on the east the picturesque valley of Encombe, called ' the Golden 

 Bowl.' 



The stone quarried in the Isle of Purbeck is locally known as * Purbeck 

 Portland.' The old quarries of Tilly Whim, near Durlston Head, are well known 

 to visitors to Swanage ; the good beds of stone having been worked out in tunnels 

 and galleries. The stone here is said to be harder than that of Portland j it was 

 last worked about the year 1812. 



1 R. Hunt and F. W. Rudler, Guide to Museum Pract. Geol., edit. 4, p. 38. 



^ See C. E. Robinson, Picturesque Rambles in the Isle of Purbeck, 1882, 

 p. 145 ; and Sir Henry C. Englefield, Picturesque Beauties, etc., of the Isle of 

 Wight, 1816, with geological sketches of the Dorset Coast, etc., byT. Webster. 



