On Variety of Colour in Efjtjs of Black-headed Gidl. 333 



is in the South of England and North of France — tliat it is 

 no easy matter to convince scientific men of their presence. 

 Even ii|) till now the Ilev. Mr Wilson, an enthusiastic inves- 

 tigator, has not found any implements stratified. I have 

 shown them to many persons bedded deep in stratified 

 gravels in almost inaccessible localities on the heughs from 

 50 to 350 ft. up, and wish Mr Wilson would search carefully 

 for them, for the conversion of such a good man and true 

 would soon lead to tlie general acceptation of the fact. The 

 beds, in or on which they have been found on the coast of 

 Ayrshire and here, have once — namely, in preglacial times — 

 been the old gravel terraces of the river Kelvin (when it 

 sv/ept round Corsewall) and of the Clyde, which passed 

 through Loch Eyan to Luce Bay. Later they were redis- 

 tributed into estuarine, and later still in late glacial times 

 into marine, beds. They bear much resemblance to the valley 

 gravels of the South of England and the Somme Valley — but 

 after their redistribution the lower members were clad with 

 a till as the Hessle gravels were in the North- AVest of Eng- 

 land. It is, however, questionable if any of the implements 

 in the old shore gravels and tills mentioned above date back 

 beyond the last eighth of the ice age. 



XXXI 1 1. Note on the Great Variety of Colour in the Eggs of 

 the Black-headed Gnll (Larus ridibundus, L.). By John 

 Alex. Smith, Esq., M.D. [Specimens exhibited.] 



(Read 21st Febrimry 1883). 



Naturalists are aU aware that though the colouring of the 

 eggs of different birds generally show a great similarity in 

 the general body colour of the shell, and also of the various 

 colours and arrangement of the spots over the shell, still 

 there is not anything like an absolute uniformity, as indeed 

 might be expected, as well from the varying age of the birds 

 themselves, as also from the state of health of the individual 

 bird. Some species of birds appear, however, to sliow a 

 greater range of colour in their eggs— both of the body colour 

 of the shell and also of the colours and arrangements of the 

 spots which may more or less cover its surface. 



