DEPOSITS OF THE SUSSEX COAST. 351 



source from which it was probably derived. No boulder is included 

 in the list unless it was firmly fixed in the clay ; the large detached 

 erratics have been well described by Godwin-Austen. 



Eeeatic Blocks eeom Medmerrt, itear Selset. 



[Measurements are given in feet. A note of interrogation shows that the full 

 measurements could not he obtained, owing to the boulder being sunk in a 

 pit or surroimded by water.2 



rfi'OTr. Po V. "rin- I Cream "Coloured limestone, full of casts oi Limncea: 



ffrom Bern bridge 

 Ledge, Isle of Wight) 



Xi; lx(?); 2x(?); iix(?); lx(?). 



/^Hard sandstone or calcareous grit, usually with 



-rj T? ir I Fectunculus brevirostris : 3|x3.jXl; 12 (much 



,n -D°" T 1 \ i shattered : perhaps .more than one erratic) ; 



(from Bognor Ledge). ] 5x4x(?) (striated); 4x4 X(?); 2xHx(?); 



^ 1^ X 1 ; 2 X (?) ; r>i X4 X (?) ; 1 X (?) (bored). 



(probabTrnTcarried 1 areywether Sandstone , l^Xli; 2x2xH; lx(?); 

 far). J '^^^^^■ 



Upper Chalk. Black flints. 



/^ Glauconitic sandstone with phosphatic nodules: 



Upper Greensand j Q^ee^^'calcareous sandstone : 2 X 1 X U. 

 ^probably ih-omtne ^^ ^^^^^^^^ sandstone with phosphatic nodules : 1 X (?). 

 s e o ig ^ ;• j Park-coloured chert, usually full of sponge-spicules : 



1^ lx(?); lixl; 1x1; lx(?); lx(?). 

 f Hard, pale-green, and reddish sandstone : l^X 1. 

 Palgeozoie. \ Greenstone: lx(?). 



[ Muscovite-biotite-granite : 1 X^. 



Por comparison, I add a list of the erratics found in newer de- 

 posits in the neighbourhood of Selsey : — 



Bognor Eock. 



Greywether (sometimes large blocks). 



Greensand chert (small pebbles). 



Hard purple grit. 



Felsite. 



Felspar-porphyry. 



Diorite. 



Greenstone. 



Granite, coarse-grained gneissose biotite (in the Selsey mud-deposit). 



Granite, coarse-grained biotite. 



Granite, fine-grained biotite. 



Granite, with large porphyritic crystals of white orthoclase. 



Granite, hornblende-biotite. 



Granite, hornblende-biotite, or possibly quartz-mica-diorite.^ 



The first thing that strikes one in the above list is the prepond- 

 erance of erratics from known localities not more than 20 miles 

 from Selsey. Previous writers do not allude to the occurrence of 

 characteristic Isle of Wight rocks, and before the exposure of the 



^ Prof. Bonney, who examined the specimens immediately before the reading 

 of the paper, remarked that many of the rocks reminded him of types met with 

 in Britanny. One specimen — the granite with large crystals of white orthoclase 

 — was, he observed, more probably of Cornish origin. 



