Proceedings, 99 



Evening Meeting. — December 14th, 1883. 



The thanks of the Club were given to Mr. A. Bennett, of 

 Croydon, for a copy of his pamphlet on ' Najas Marina as a 

 British Plant.' 



Dr. Bossey showed under the microscope some Foraminifera 

 from the Gault Clay of Wray Common. 



The President then read ' Notes on a Eecent Visit to the 

 Isle of Portland.' He called attention to the tendency of the 

 land in England to run into points tending south and west. 

 Portland is not, strictly speaking, an island, being joined to 

 the mainland by Chesil Bank, a ridge about ten miles long 

 and from a quarter of a mile to a mile in width. 



The Isle of Portland is about four miles long from north to 

 south, and a mile and a half broad in its broadest part. In 

 shape it is like an elongated egg. Its greatest elevation 

 above the sea is 495 feet ; it rises rapidly on the north, and 

 slopes on its southern end to about thirty or forty feet above 

 the sea. Portland is one vast rock, chiefly of the geological 

 series called Upper Oolite, composed, however, of various 

 strata belonging to that series ; it is of marine formation. 

 The rock is removed for building- stone, which is of a very 

 superior character, St. Paul's Cathedral is built of it, and 

 blocks rejected by Sir Christopher Wren still lie about, none 

 the worse for exposure. 



The island rests on a bed of Kimmeridge Clay, so called from 

 a village in Dorsetshire, where it has been found near the 

 surface ; this clay is in some places bituminous, and works 

 were at one time erected for the manufacture of oil and 

 paraffin ; it has also been, in times of scarcity of coal, used 

 for fuel, but yields disagreeable fumes, and hence the manu- 

 factory itself was discontinued. On this foundation of 

 Kimmeridge Clay lies about eighty feet of what is termed 

 Portland Sand, of somewhat ferruginous character ; not all 

 loose sand, but sandy rock, with layers of indurated sand. 

 Over this is about forty feet of impure limestone, mixed with 

 chert and flint, the chert sometimes in layers, sometimes in 

 detached pieces ; the flint also is not like flint in chalk in 



