288 The Irish Naturalist, [Nov., 



that his gravel-bed is without doubt a fragment of the ancient 

 Post-tertiary beach which up to the present has not been 

 obliterated by extension of the town, though recent observers 

 have referred to it as now inaccessible. The exposure at 

 present available is described by Mr. Patterson as being some 

 30 feet long by about 3 feet thick,* and lies a few feet above 

 high-water mark. It marks the northward extension of the 

 old beach, or raised sea-bottom. It is not a beach in the true 

 sense, many of the shells being such as live at a considerable 

 depth, and the grouping is such as not likely to be found on 

 an ordinary beach. 



Portlock, in 1843, first called attention to this accumulation 

 at Portrush of sand and gravel so highly charged with shells. 

 He enumerated, on the authority of Smith, 79 species of 

 Mollusca as found therein, together with some Annelids and 

 Balaiii. Grainger subsequently examined these gravels, and 

 published a list of 54 species of fossils found by him, a number 

 of w^hich being additional to those previously recorded. Con- 

 siderable attention was paid to this beach later on, and in the 

 British Association Report for 1890, Mr. Alfred Bell, of 

 London, who himself has added considerably to the list, gives 

 113 species of Mollusca as having been found in the Portrush 

 beach up to that date. 



B}^ the list which follows it will be seen that 48 species of 

 marine Mollusca are represented in the small quantity of 

 material handed me by Mr. Patterson. A considerable propor- 

 tion of these are shells which may be found between high and 

 low-water marks, a good many do not come up to low-water 

 mark, but the largest portion consists of species which range 

 from low-water to many fathoms below it, shells of the Lami- 

 narian and Coralline zones. The geographical facies is slightly 

 northern. The northern aspect is not emphatic, but never- 

 theless, taking Jeffreys's British Coiichology as our guide, it 

 appears that not one is characterized as southern, while four 

 species are considered as having a northern range. These, 

 however, are only mildly northern. 



* These dimensions apply only to the section seen by Mr. Patterson, as 

 the gravels, in their further extension, are covered by soil. 



