F. W. Harmer — The Coralline Crag Molluscan Fauna. 27 



than proceed to draw inferences as to annual rates of loss from these 

 recent observations. 



To complete my tale, I should mention that the heavy rains of 

 July last had a farther disastrous effect upon the new faces of sandy 

 cliff at Southwold, and again much loosened material has fallen, 

 but this time not by direct marine agency. The worst feature of 

 the case is the delay attendant upon Parliamentary proceedings to 

 obtain the necessary sanction for carrying out the protective works, 

 as another winter must inevitably intervene before they can be put 

 in hand, and no temporary expedients of a satisfactory character 

 have been suggested. 



[The paper was illustrated by photographs and a water-colour 

 sketch of the new cove at Southwold.] 



VI. — The Southern Character op the Molluscan Fauna of 

 the Coralline Crag Tested by an Analysis of its more 

 Abundant and Characteristic Species. 1 

 By F. W. Harmer, F.G.S. 

 ri^HE close resemblance between the Molluscan fauna of the 

 J Coralline Crag and that of the Mediterranean at the present 

 day has long been known and is universally recognized. It has 

 been customary, however, to take the whole list of shells from this 

 deposit, for the purpose of comparison, without reference to the 

 greater or less abundance of the different species ; but in discussing 

 the affinities of the fauna from this, or indeed from any other 

 horizon of the East Anglian Crags, it may be misleading to attach 

 as much importance to the presence of a shell, of which only one or 

 at the most a very few specimens have been discovered during so 

 many years, as to the occurrence of forms which are found in such 

 countless profusion as sometimes to compose a large proportion of the 

 whole number of the shells present. Out of about 410 species of 

 Mollusca from the Coralline Crag given by Mr. Wood in his well- 

 known Monograph 3 (excluding varieties), nearly 90 are said to be 

 represented by unique specimens only, while more than 100 others 

 have very rarely been met with. It is true that some of these 

 rarer forms may be only locally rare, although it is worthy of 

 notice that, with few exceptions, the species which are common in 

 the Diestien beds of Belgium, 3 believed to be approximately con- 

 temporaneous with the Coralline Crag, are also common in that 

 deposit. On the whole, without ignoring altogether the existence 

 of the rarer forms, it seems that a consideration of the general 

 facies of the fauna of each of the different horizons of the Crag, 

 and of its characteristic fossils, is more important and is likely 

 to give more reliable results than an analysis of all the species 

 of each bed, irrespective of the greater or less frequency with which 

 they have been found. 



1 Read before Section C of the British Association at Ipswich, Sept. 12th, 1895. 

 3 Palseontographical Society (1848, etc.). 



3 Van den Broeck, Introduction au Memoire de M. P. H. Nyst sur la Conchy - 

 liologie des Terrains tertiaires de la Belgique. Bruxelles (1882). 



