206 MR. E. B. WETHERED ON THE [May 1 895. 



Fig. 5. Oolitic granule from the Coralline Oolite, Weymouth. The upper 

 portion of the crust shows concentric arrangement, which gradually 

 terminates towards the lower portion, and is finally replaced by 

 a confused mass of dark spots sui'rounded by calcite. These are 

 assumed to be the filled-in openings of organic structure seen in 

 plan. Similar spots occur in the concentric structure, and are 

 regarded as the same, only sliced in section. X65 diam. 



6. a & b. From the Forest Marble near Cirencester. The first (a) is 



a reproduction from a positive photograph ; b is the same object 

 as it appears in a negative photograph. As in the case of fig. 4, 

 the intention is to illustrate that the granule is made up of cal- 

 cium carbonate existing in two conditions, namely the ' clear,' which 

 is dark in the negative picture and light in the positive, and the 

 'granular amorphous' condition, which in the positive illustration 

 is dark and in the negative white. 



The ' granular amorphous ' calcium carbonate is regarded as 

 infilling or secreted material, and the 'clear' in the positive and 

 dark in the negative as representing the organic structural part of 

 the granules. X 65 diam. 



7. From the Coralline Oolite near Weymouth. This is a type of granule 



in which no concentric limestone is apparent. The structure is 

 similar to that in the non-concentric portion of fig. 5. X65 

 diam. 



8. From the Coralline Oolite near Weymouth. This granule shows 



a mass of minute Girvanellce surrounded by a crust of concentric- 

 ally-growing tubules with distinct walls. x65 diam. 



9. From the Forest Marble near Cirencester. This granule has un- 



dergone considerable mineralogical changes. The dark portion is 

 ' granular amorphous ' calcium carbonate, which is either secreted 

 or infilling material ; this has not changed. The ' clear ' portion 

 represents the organic structure, and in places this has been con- 

 verted into minute needles of calcite at right angles to the irre- 

 gular concentric growth (see A). X t>5 diam. 

 10. This figure is not referred to in the text : it is a granule from the 

 Cai'boniferous Limestone near Buxton, and is in all respects of 

 similar origin to that shown in fig. 1, namely, the growth around 

 a nucleus of tubular bodies of organic formation. 



Discussion. 



The President congratulated the Author on the excellent manner 

 in which he had put the subject of the paper before the Society. 

 Whether he had established the organic origin of oolitic granules 

 generally, or had not, he had at least placed the material upon 

 which his views were based most admirably upon the screen. He 

 (the President) had studied orbicular calcite in rocks and in fossil 

 organisms, and had often believed that he was dealing with organic 

 structures, whereas they were only concretionary. He thought that 

 the Author had placed evidence before the Meeting sufficient to 

 prove the organic origin of many of his oolitic granules. 



Mr. G. P. Harris thought that this was a very valuable contri- 

 bution to our knowledge of the origin of oolites : but while most 

 geologists would possibly agree as to the organic nature of the 

 tubules in the pisolites referred to, he believed that they would not 

 be unanimous in recognizing the tubular structure in many of the 

 oolitic granules shown. If the concentric lineations exhibited by 



