Vol. 56.] LIMESTONES EROM KATHIAWAK, ETC. 575 



•occur : many of these are likewise covered by a calcareous envelope. 

 The stratification is necessarily false-bedded, but the lamination of 

 the most recent layer is usually parallel to the surface of the beach ; 

 this is in most cases quite loose above, though a few feet lower down 

 it is cemented into a solid mass, the result of the infiltration of 

 water containing carbonate of lime from the upper part of the deposit. 

 Turtles' eggs are often found, even in the consolidated rock. 



Such calcareous beaches are especially characteristic of coral- 

 islands, but are by no means confined to them. 



The typical coral-island beach has been well described by Dana 

 [28] pp. 152-54 ; see also Beete Jukes for the beach-deposits of 

 Raine Island [15] ; and Guppy [24] pp. 84-85, for an account of 

 such beaches in the Solomon Islands. Darwin's description of the 

 oolite-beach at Ascension is well-known : see [14] pp. 49-50 ; 

 [27] A pp. 56-57 & B pp. 198-9 ; also [11 j. A specimen of the 

 Ascension rock, containing remains of turtles' eggs, is in the Museum 

 •of the Geological Society. A raised oolite-beach in the Gulf of Suez 

 has been briefly described by Mr. Bauerman [19]. 



(c) Deposits usually found above high-water mark, 

 containing no large marine remains, although 

 the small grains which compose the rock are 

 clearly of marine origin. 



These consist for the most part of minute fragments of shells, 

 corals, or limestone, or occasionally foraminifera, which are coated 

 with deposited carbonate of lime exactly in the same manner as in 

 the two other classes ; and in this class, too, oolite-grains occur. 

 The stratification is, as a rule, distinctly false-bedded. These rocks 

 appear to be formed, like the Junagarh Limestone, by the action of 

 the wind on the calcareous beach-deposits in sifting out the smaller 

 and more rounded grains, and transporting them inland. In the 

 majority of cases, land-shells or other remains of terrestrial animals 

 are present. 



The island of Bermuda [13, 20, 23, 31, 33] and the Bahamas 

 [16, 31] are mainly formed of this rock. Through the kindness of 

 the Council of the Geological Society, I have been allowed to have 

 microscope-sections cut from one specimen of the Bermuda rock and 

 from two specimens of the Bahama rock in the Society's collection. 

 These show great resemblance to the Kathiawar limestones in the 

 well-developed matrix of clear calcite and numerous fragments of 

 marine organisms, with a dark calcareous coating ; but in one of 

 the Bahama specimens the oolite-grains are much better developed 

 than is usually the case with the Kathiawar rocks. 



Similar deposits also occur in the Canary Islands [12] and at 

 St. Helena [14] pp. 86-89, [27] A pp. 98-101 & B pp. 222-24 : 

 see also [22]. Extensive calcareous beds which are supposed to be 

 4>f aeolian origin have been described by Darwin in Western Australia; 

 but he could not find in the grains anything definitely organic [14] 

 pp. 144-48 ; [27] A pp. 161-66, B pp. 260-63 ; & [17]. Low 



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