260 Notices and Extracts from the Minutes of the Geological Society. 



20 feet in perpendicular descent beneath the first bed*. It appears to be of 

 greater magnitude^ as some of the masses are so large that not a crack appears 

 over a surface of 30 feet. 



On the top of the clitfs, about 20 years ago, was a patch of crag, which has 

 been entirely destroyed. 



In the southern prolongation of the cliff, in that part which extends about 

 three quarters of a mile, the clay is divided by only four whitish streaks, and 

 is nearly the same from top to bottom. 



The thickness of the formation in Harwich is inconsiderable, the chalk 

 having been found at the depth of only 60 feet from the surface ; and though 

 there is a great accumulation of alluvial matter on the peninsula on which 

 the town stands. 



Iron pyrites occur abundantly, and lignite is found, but not in considerable 

 quantities. 



Fossils are principally procured from the cement-stone, the most common 

 being a Venus. Nautili are sometimes found, and Mytili with the nacre ; also 

 a species of Patella. 



The cement-stone, when it first falls from the cliff, is rather soft, but after 

 exposure for some time it becomes very hard. Being of a black colour it is 

 usually mixed with cement made from the Whitstable stone, and is less valu- 

 able than the Sheppey. The greater darkness of the colour is attributed to 

 the greater quantity of manganese. 



The cliff at Felixstowe, about three miles north of Languard Fort, consists 

 of blue London clay, similar to that at the foot of the Harwich cliff; and on 

 the top is a stratum of crag from 10 to 15 feet thick, the London clay being* 

 about 35 feet. No cement stone is seen in the cliff, but at low water, two beds 

 may be found at the same perpendicular distance from each other as at Har- 

 wich. 



2. — Notices of the Red Marl and Lias of Worcestershire ; of a Fault hy which 

 they are affected; and oj fossil freshwater Shells at Shotovcr Hill. By 

 Hugh Edwin Strickland, Esq., F.G.S. [Read December 4th, 1833.] 



These notices were accompanied by a manuscript map, on which are laid 

 down, with greater accuracy than had before been attempted, the boun- 

 daries of the red marl and lias in the districts adjacent to Pershore, Evesham, 



* This measurement was ascertained during the sinking of a well in the fort, on the hill at the 

 south side of the town. 



