454 Mr. A. Hancock on Vermiform Fossils. 



form certainly gives to it much the appearance of some organism. 

 An endeavour, however, has already been made to explain the 

 nature of this peculiar character ; but whether successfully or 

 not, there is sufficient evidence to prove that these fossils are 

 not organic. The slabs exhibiting these vermiform tracks are 

 frequently marked with numerous small pits or punctures, which 

 sink for a short distance beneath the surface. These (PI. XVII. 

 c, c) have somewhat the appearance of what have been termed 

 by geologists impressions of rain-drops. In this instance, how- 

 ever, they are undoubtedly produced by the animals which have 

 made some of the smaller tracks, as it is not uncommon to see 

 the latter terminate in one of these punctures (e,e). Now, it 

 occasionally happens that the large or striated fossils are per- 

 forated by these punctures ; and the scars thus made are similar 

 to those in like manner formed on the other parts of the slab. 

 This could hardly be so, had the slab and the fossil been origi- 

 nally composed of two different substances, — that is, had the 

 former been nothing but sand or mud, and the latter a worm- 

 tube or some other organic body. 



Another fact equally instructive may also be cited. The slab 

 in the Newcastle Museum previously alluded to exhibits not only 

 the large grooved track, but also several of the small furrowed 

 ones ; and the latter frequently pass over the former in various 

 directions (PI. XVIII. c, c, c). The nature of the small species 

 is not likely to be disputed : it is certainly a track of some kind ; 

 and it is remarkable that it never turns aside as it approaches 

 the large grooved form, but passes over it at once, ploughing its 

 way exactly in the same manner as it has done on the level por- 

 tions of the sandy beach. The furrow is precisely of the same 

 character, form, and depth, whether on the slab or on the track ; 

 and the ridge thrown up on each side is in no respect dissimilar. 

 This seems a pretty conclusive proof that this large vermiform 

 fossil is not a worm-tube or any organic body, but is really no- 

 thing more than a track which was, in fact, originally, as it is now, 

 composed of the same material as the slab upon which it rests; 

 otherwise the appearances as above described could not exist. 



There still remains another very conclusive argument, against 

 the organic nature of these fossils. The folds or windings of both 

 the grooved and nodulous forms occasionally cross each other; 

 and when they do so, the one does not lie over the other, as it 

 must necessarily have done were they organic, but passes right 

 through it, cutting its own path (PI. XVII. b). This is still 

 more clearly demonstrated in the fine large specimen of the no- 

 dulous form previously alluded to (PI. XVI. b, b), and appears 

 only explicable on the hypothesis of their being mere tracks. 

 And perhaps it will now be allowed that enough has been said to 

 establish the high probability, at least, that they were formed by 



