1858.] WOOD RED CEAG. 39 



are procured only from the lower stratum, or that in which the 

 phosphatic nodules are obtained. 



Specimens of wood, of a tropical character, are frequently met 

 with in association with these animal remains : I have found such 

 pieces of wood perforated with existing Pholades (Ph. parva and 

 Ph. crisjpata), the wood itself being in a lapideous or metalliferous 

 condition ; but this metallic impregnation may perhaps have been 

 derived from the mineral matter of the Red Crag, subsequent to the 

 removal of the fossil from the London Clay; the tube of Teredo 

 antenautce is found in the same bed, but I have not met with this 

 species in the Eed Crag, in what may be called its natural habi- 

 tation. 



A number of indeterminable, or at least undetermined, fossils 

 have been obtained from the Eed Crag, which, as to their deriva- 

 tion, may be referred to the London Clay. I would especially par- 

 ticularize some spiraUy-formed bodies which have been regarded as 

 the coprolitic rejectamenta of the Shark tribe, as these animals 

 have a spiral intestine. The Crag fossils in question appear to me 

 to be rolled and water- worn specimens similar to some Serpula- 

 form bodies which have been found in the London Clay of High- 

 gate, figured and described in the Mag. Nat. Hist. 1839, pi. 8. 

 fig. 15, by Mr. N. T. Wetherell. Whatever may be the nature of 

 these spiral fossils, and whenever their characters shall have been 

 determined by the more perfect specimens of the London Clay, 

 there is, I think, little doubt but that the Crag specimens of the so- 

 called spiral '^ coprolites" have the same origin, and were derived 

 from the same formation. The projecting spiral in the Crag fossil 

 is different from the clay contained within its fold, and not homo- 

 geneous, as it would have been, if it were of coprolitic origin. 

 Another Crag fossil is, I think, worthy of some remark. It re- 

 sembles pi. 1. figs. 1 & la of the Mag. Nat. Hist, for 1839 before 

 referred to ; indeed there is no doubt of the identity with the London 

 Clay specimens. They are inserted among the fossils Incertce sedis 

 in * Morris's Catalogue of Brit. Possils,' under the name of Nidu- 

 lites (Salter). These small bodies have been considered by Mr. 

 Prestwich (Geol. Journ. vol. viii. p. 247, pi. 16. fig. 11) as the eggs 

 of Mollusca, and by others as the spawn of Crustacea ; they have 

 also been referred to a coprolitic origin ; but that they are the ova 

 of some animal seems the better opinion*. They appear too re- 

 gular in their arrangement to be the seeds of any vegetable. 



My list contains the names of 109 species of true derivative 

 fossils ; and of this number there are 57 which can be traced to the 

 London Clay, or at least to the Older Tertiaries, with a few others 

 probably from the same formation, but not in a sufficiently perfect 

 condition for determination : 30 have belonged to a much more 

 recent date ; 9 were Chalk fossils ; 4 appear to have been derived 

 from the lias or Lower Oolite ; and, if the identifications be cor- 



* See also Mr. Wetherell's paper " On Certain Nodules of the London Clay 

 in the Crag," supra, p. 32. 



