Yol. 56.] LIMESTONES FROM KATHIAWAE, ETC. 579 



than the oolite-grains, it may represent another phase of beach- 

 formation. In some parts, for instance, of the Great Oolite the 

 organic remains are so broken up, that hardly a single perfect speci- 

 men can be found : see [45] p. 298. x The Forest Marble likewise 

 contains in places large quantities of broken shells {ibid. p. 305). 



There seems every reason to believe that seolian deposits, too, are 

 not wanting among the Jurassic oolite-rocks. Oolitic grains are, 

 from their size and shape, especially susceptible of transport by the 

 action of the wind, and grains consisting of organic or other particles, 

 with a single coating of deposited carbonate of lime, are sufficiently 

 rounded to be transported almost as easily. When a rock is found 

 to be made up almost entirely of such grains, without larger fossil 

 remains, we may suspect that it was formed by wind-action. 2 This 

 presumption is strengthened where the cement, binding the grains 

 together, is comparatively clear calcite, as in the Junagarh and other 

 Kathiawar seolian limestones (see also [52^ p. 103), and does not 

 consist of turbid consolidated calcareous mud, as in the case of 

 some oolitic limestones [46] pp. 8, 12, which must, as I have said, 

 have been deposited as submarine or littoral deposits. The ex- 

 ceptional Oolite-rocks in which there is no cement whatever, [46] 

 p. 12, are probably also of seolian origin. 3 



We have seen that at the time when the turtles' and other 

 reptilian eggs were buried, the calcareous beach-deposits of the 

 Bathonian Epoch, in which they are now found, must in all 

 probability have been situated near the sea-margin, a little above 

 high water, in just such a position as we might expect wind-borne 

 material to accumulate ; for the line of high water at spring-tides is 

 often marked on low shores by a ridge of sand. 4 We ought not, 

 therefore, to be surprised if the strata succeeding the beds in the 

 Great Oolite Series, where these reptilian eggs occur, prove to be of 

 seolian origin. At various points in the Great Oolite the rock does 

 in fact exhibit many of the characters of a wind-formed deposit 

 In hand-specimens it shows a remarkable resemblance to some of 

 the Kathiawar and West-Indian seolian rocks, and in some cases, 



1 The conglomeratic structure sometimes seen in the Great Oolite also points 

 to littoral deposition. 



2 The thin delicate shells of oceanic gasteropoda and certain other mollusca, 

 although of fairly large dimensions, may sometimes be blown inland [23] p. 321 , 

 but, like land-shells, are liable to be destroyed before the consolidation of the 

 rock, or obliterated by recrystallization. The presence of a few isolated shells 

 may also be explained by the action of shellfish-eating birds or animals (see 

 p. 576 of this paper). Hermit-crabs are responsible for some marine gastero- 

 poda in recent seolian deposits [23] p. 321. 



3 Mr. Horace B. Woodward, in describing the deposits characteristic of coral- 

 islands, refers to the false-bedded calcareous geolian rocks of the Bahamas, and 

 quotes Dana -to the effect that similar rocks are frequently oolitic. He after- 

 wards remarks that ' it is a study of these sedimentary and other accumulations 

 due to the destruction of coral-reefs that will help to explain the origin of our 

 oolitic deposits.' But he appears to consider 'the false-bedded character of 

 so many of the Oolites ' as exclusively a subaqueous phenomenon : see [46] 

 pp. 17-18. 



4 Much of the foraminiferal material in Dog's Bay is accumulated just above 

 high-water mark. 



