552 Dr. F. A. Bather — Tube-building Fossil Ann elides. 



tube. All this ornament is simply a surface appearance ; there does 

 not as a rule seem to be any definite tube-wall. 



Some specimens, however [e.g. A 1577, A 1582], show, in addition 

 to the cancellar ornament, a fine-grained linear striation crossing the 

 tube at an angle of about 45° (Fig. 4). This seems to be of semi- 

 crystalline nature like the structure usually known as 'beef. It is 

 presumably due to a physico-chemical action of the supposed gelatinous 

 tube on the surrounding ooze. In A 1582 the striae run from left 

 downwards to right, but in A 1577 from left upwards to right. 



The Upper Greensand specimen [A 1638] is the only one in which 

 I have noted anything suggestive of an original tube- wall. Here in 

 places there seems to be a thin coating of darker, denser, fine-grained 

 (or crypto -crystalline) rock, but it is very indefinite. 



The ornament just described forms an additional reason for refusing 

 to assign these tubes to Terebella leivesiensis without far more convincing 

 evidence than that adduced by Davies. 



What these fossils may be is a different question which would be 

 better discussed by one more fully acquainted with the possible living 

 organisms than I am, and after examination of far more material than 

 is as yet at my disposal. 



Specimen A 1638, collected from the Upper Greensand of Betchworth 

 by the donor, Mr. G. E. Dibley, has been refen-ed to by him as "an 

 unusually large Bacculite " (Proc. Geol. Assoc, vol. xxi, p. 485, 

 Aug., 1910). To this conception of the specimen he was doubtless 

 led by the peculiar curvature of the strongly marked transverse folds 

 in some regions. Mr. G. C. Crick, however, does not claim it for this 

 or any other kind of Cephalopod. 



These and similar fossils from the Chalk are usually called 'fucoids '. 

 How any imaginable fucoid, or any other form of vegetable growth, 

 can have resulted in a fossil of this description has never been clear to 

 me ; but, since Dr. Stopes declines to include them in her Catalogue 

 of Cretaceous Plants, any who still believe in their fucoid nature may 

 be left to argue the matter with her. 



It seems quite certain that these fossils represent tubes, which lay 

 on the sea-floor or in the semi-floating ooze of which it consisted, and, 

 either being deserted by the creature that formed them or persisting 

 after its death and decay, were filled with the ooze in which they lay. 

 The tube- wall, it is clear, was of such strength and consistency as to 

 retain its form fairly well during this process, and yet of such 

 composition that it disappeared after the partial consolidation of the 

 ooze. The markings on the infilling of the tube may be due to two 

 causes ; either a similar folding of the tube-wall during life, or 

 a wrinkling and contraction of the tube after death and perhaps even 

 after burial. The relative regularity, constancy, and peculiar 

 curvature of the transverse folds suggest that they were originally 

 present in the tube, and that they may have been connected with 

 the ringed structure of the tube-builder. On the other hand, the 

 irregularity and very varying development of the longitudinal folds 

 suggest that they, at least, were due to post-mortem changes. 



From the Cretaceous beds of the European Continent, and notably 

 from the Flysch, a large number of supposed fucoids have been 



