106 TRANSACTIONS OF THE [jAN. 18, 



water a limestone,* whose structure could not be made out. 

 There appear to be traces of lamination like that of the sand- 

 stone, but the blown sand, soft though it is, has oliscured the 

 structure and roughened the surface. This rock is not like the 

 limestone or the sandstone, which is shown at eight feet higher ; 

 nor does it resemble the intermediate deposit in an}- of its 

 phases elsewhere ; but it holds the place of the last and is prob- 

 ably continuous with it. It is composed of fragments of nulli- 

 pore and millepore with occasional bits of shells and is rather 

 coarser than the coarsest sands seen at Tuckertown. 



Ireland island terminates the 'hook.' Near its southern end 

 Professor Ricef found, just above the water level, a slightly 

 consolidated rock containing marine forms and passing gradu- 

 ally upward into the helix bed. The latter is shown on the 

 south shore near the cut midway in the island, but the writer 

 was not fortunate enough to find marine forms in the underlying 

 rock. 



It is convenient for description and for reference in the dis- 

 cussion to bring together here all of the Beach rocks, as the}- 

 are in large part continuous with the intermediate deposit. 



A beach rock, described by Nelson and frequently referred to 

 by Rice, occurs on the islands between Ireland island and 

 Spanish point on Hamilton. It underlies the sandstone on 

 those islands and extends certainly to 16 feet below the water 

 surface, for fragments of it were blasted out in 1895 during the 

 deepening of Stag channel off Ireland island, where it was found 

 associated with red clay. It is evidentl_v continuous with the 

 ' coralcrust ' found in the great excavation on Ireland, where it 

 overlies sandstone, which in turn overlies the Helix bed and the 

 soil resting on the deeply eroded limestone. A similar rock ap- 

 pears to be present on the ledge flats near North Rock.| 



The Limestone, 



The limestone is the lowest of the rocks now above water 

 level and it is spoken of commonly as the '' base rock." It is 

 shown at ver}^ many localities along the south shore to near 

 Tuckertown, where one reaches the almost continuous exposure 

 extending along the southwesterly side of Castle harbor and 

 passing across to the north corner of Harrington Sound. Bosses 

 of this rock appear above the water on Pear Island, in Harring- 

 ton Sound, at several points along the road following the north- 

 easterly and easterly shores of that sound, and in Pembroke 



* Mentioned by Rice, loc. cit., p. 14. 



fLoc. cit., p. 13. 



JHeilprin, Tbe Bermudas, p. 38. 



