406^ Geological Society, 



bones. They are supplementary to the atlas, axis, and third ver- 

 tebra of the neck, and seem to have escaped the observation of 

 Cuvier and other osteologists. 



Mr. Lewis Hunton has communicated to the Society an elaborate 

 account of a section of the upper lias and marlstone in Yorkshire, 

 showing that different beds in those formations are characterized 

 by particular species of Ammonites and other Testacea, each species 

 having a limited vertical range. His observations are valuable not 

 only as illustrating the distribution of fossils on the coast near 

 Whitby, but also as furnishing a point of comparison between that 

 district and many others in Great Britain. Mr. W. C. Williamson 

 of Manchester has had the same object in view in studying the fos- 

 sils of the oolitic formations of the coast of Yorkshire, and informs 

 us, as the result of his patient investigation, that although certain as- 

 semblages of fossils abound in particular subdivisions of the oolite, 

 many species range from the lowermost to nearly the highest beds. 

 This inference is confirmed when we compare the lists drawn up 

 by Mr. Williamson, and those published by Professor Phillips and 

 other competent authorities. Thus some of the shells of the in- 

 ferior oolite, mentioned in Mr. Williamson's list {Trigonia gibbosa, 

 for example), occur also in the Portland-stone of Wiltshire ; another, 

 as Ostrea Marshii, is characteristic of the cornbrash in the same 

 county ; others pass downwards to the lias, as Orbicula reflexa and 

 Ammonites striatulus. If you consult the tables of organic remains 

 which Dr. Fitton has annexed to his excellent monograph on the 

 strata below the chalk, just published in our Transactions, (2nd Se- 

 ries, vol. iv. part 2.) you will see that a considerable number of 

 shells pass from the upper oolitic groups into the green-sand. We 

 are not to conclude from these facts that certain sets of fossils may 

 not serve as good chronological tests of geological periods, but we 

 must b^ cautious not to attach too much importance to particular 

 species, some of which may have a wider, others a more limited 

 vertical range. The phaenomena alluded to are strictly analogous 

 to those with which we are familiar in the more modern deposits, 

 where different tertiary formations contain some peculiar Testacea, 

 together with others common to older or newer groups, or where 

 shells of species now living in the sea are associated with others that 

 are extinct. 



An assemblage of fossil shells has been presented to our museum 

 by Mr. J. Leigh and Mr. J. W. Binney, found at Collyhurst near 

 Manchester, in red and variegated marls, which were referred by 

 them at first to the upper division of the new red sandstone group; 

 but Professors Sedgwick and Phillips consider them to be a red and 

 variegated deposit, belonging to the magnesian limestone series. 

 As these fossils are new and characteristic of a particular subdivi- 

 sion of the beds between the lias and coal, it is to be hoped that 

 they will soon be described and figured. 



The petrifaction of wood, and more especially its silicification, 

 still continues to present obscure problems to the botanist and 



