336 Transactions of the Society. 



minute organisms which at first sight seemed to be Eadiolarians. 

 Upon sketching them I was struck with their comparatively large 

 dimensions. Their average diameter was about 1 mm., whereas 

 the Spumellarian Eadiolaria generally measure one-sixth of that. 

 Moreover the bent and twisted appearance of some of their spines 

 seemed to point to a flexibility seen in spores, but not so strikingly 

 exhibited in the Eadiolaria. 



The late Dr. W. C. Williamson made a special study of small 

 bodies in Carboniferous rocks, which he named Sporocarpon and 

 Zygosporitcs, and also referred to the genus Traquairia of Carruthers. 

 These organisms are generally spherical and with radiating spines. 

 The spheres frequently enclose smaller rounded bodies, and were 

 consequently regarded by Williamson as megaspheres having 

 Lepidodendroid affinities.* 



The present examples are about twice the diameter of those 

 found by Williamson in the Carboniferous of Yorkshire and else- 

 where, but in every other way resemble them. Other smaller 

 bodies, often numerously represented in the Carboniferous Lime- 

 stone of Britain, were termed by Williamson Galcisphmrm. They 

 were regarded by Professors Sollas and Judd as true Eadiolaria, 

 with which they compare both in size and shape, and in having in 

 some cases slender spines. The ornament of the GaUisphierx, is 

 moreover, often like the meshwork of a Eadiolarian, but as a rule 

 much finer in texture. The chief objection that has been raised 

 against their Eadiolarian affinities is the fact that they are now in 

 the form of calcite ; but in view of the calcified Eadiolaria in the 

 Chalk this difficulty is not insuperable. 



The chief argument against their being siliceous Eadiolaria 

 replaced by calcite is that they are invariably calcareous, so far as 

 I am aware, whilst other, siliceous, bodies in the same rock are not 

 replaced by calcite. At present I am inclined to think that the 

 balance of evidence is in favour of these minute bodies bearing a 

 relationship to certain calcareous algai such as the RhaMospheres 

 and Coccospheres, which are so abundant in modern calcareous oozes.f 



Seeing the present rock samples are marine limestones (Orthis, 

 Stringocephalus and Clymenia faunas), to find the spore-like bodies, 

 here referred to Sporocarpon and Traquairia, may seem anomalous. 

 But it is just as feasible as it is to discover drifted wood in Chalk 

 (Purley, England), or in the EoUing Down Limestone (Queensland), 

 for these apparently difficultly destructible organisms may easily 

 have survived the ordeal of drifting by streams flowing into a clear 

 deep sea. 



* See Williamson, W. C, "On the Organization of the Fossil Plants of the 

 Coal Measures," pt. 10, Phil. Trans. R. Soc, vol. clxxi. pt. 2, 1889, pp. 493-539, 

 pis. xiv-xxi. 



t This was also reservedly suggested by Williamson, Phil. Trans., 1880, vol. 

 clxxi. p. 525. 



