Vol. 56.] LIMESTONES FROM KATHIAWAR, ETC. 571 



deposited in shallow water. The shell-bearing beds on the north of 

 Pacham appear to be an example, and no doubt others will be found 

 when a detailed examination of the strata comes to be made. 



The thick homogeneous beds of Ras Abu Ashrin and certain other 

 points on the south-eastern coast of Arabia, which contain no marine 

 shells or other fossils of any kind larger than the minute grains of 

 which the rock is made up, and at the same time no organic remains 

 of terrestrial origin, the Porbandar Stone, and the limestones 

 of Junagarh, Chorwar, and Una, which present similar characters, 

 give rise to greater difficulties ; though the position of the limestones 

 of Junagarh and Porbandar west of considerable hills is favourable 

 to the contention that these deposits were accumulated by the 

 south-westerly monsoon wind. 1 



In the first place, the foraminiferal tests and other organic 

 particles which form the nuclei of the grains are undoubtedly of 

 marine origin, being the remains of organisms that lived in the sea. 

 The calcareous envelope, too, surrounding these particles is so 

 similar to that which is found covering grains in admittedly sub- 

 marine beds, that we may assume that in this case also it was 

 deposited from sea-water. 



The question now arises — Were these strata laid down in shallow 

 water, or were the materials of which they are formed thrown up 

 by the waves in a calcareous beach, from which the smaller and 

 more easily transported grains were sifted out by the wind and 

 transported to their present position ? The well-developed false- 

 bedding is equally consistent with the action of the wind and with 

 that of varying currents of water saturated with carbonate of lime. 

 It is at first sight strange, if these limestones be subaerial deposits, 

 that there is no record of the occurrence of shells of terrestrial 

 mollusca ; but it is not so difficult to account for this, as for the 

 absence of larger marine remains, on the hypothesis that they are 

 strata laid down in sea-water. Land-shells are less numerous than 

 marine forms capable of preservation, and are so fragile that they 

 might easily be destroyed — either by exposure at the surface, or 

 subsequently by the action of infiltrating water. The absence of 

 large marine remains cannot be explained in this way. A con- 

 siderable part of the rock is made up of minute fragments of the 

 calcareous parts of larger organisms : the action of underground 

 water has not been able to obliterate their structure, and cannot 

 be accountable for the absence of fragments of greater size. 2 



1 The main mass of the Junagarh Limestone is, however, about ^ mile from 

 the foot of the hills, but much has no doubt been removed by the Sonrakhi 

 Kiver. I have had no opportunity of seeing either the Porbandar Stone or 

 the massive Arabian deposits in situ, so must deal principally with the rocks 

 which I have been able to examine ; but from the apparent similarity in com- 

 position and structure, there is a strong presumption that all the rocks to 

 which I am now referring were formed under the same circumstances. 



2 There are, however, some cases in which strata, supposed to have been 

 formed in the sea and made up of minute particles of marine origin, are 

 practically destitute of larger fossils. In a paper by Mr. Robert Hill on the 

 geology of Jamaica, [51] p. 137, we read: — 'As a rule the Tertiary White 



