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rently much less developed along the Woolhope border. I visited this fine 

 section when the tunnel was being made with several members of the Warwick- 

 shire Naturalists Field Club, and I recollect being much struck with it at the 

 time. Formerly these Passage Beds were classed by Sir R. Murchison with the Red 

 Sandstone, but latterly he has denominated them Passage Rocks, which seems 

 altogether more appropriate as showing their intermediate character between the 

 Old Red and the Silurian ; but some geologists, I believe, still desire to have 

 them restored to their original position in the Old Red. This, however, is a 

 question which I do Dot pretend to decide, but which future discoveries of other 

 organic remains may definitely settle, if it has not already been satisfactorily 

 determined, my object now beingrather to indicate a greater extension of this series 

 around the 'Woolhope elevation than had been previously recorded. There are 

 many interesting and important questions connected with all " Passage Beds," 

 of which several are known to occur between two great epochs of geological 

 time. It is well known that such transition periods contain several new forms 

 of life, while many of those which characterise the older formation below were 

 still in existence, and some pass upwards into the newer formation above, and 

 others are peculiar and distinctive. Take for example the Rhcetic series 

 coming in between the Trias and the Lias, the basement bed? between the Lias 

 and Inferior Oolite, and the junction beds at the top of the Wealden, between it 

 and the Lower Green Sand. Hence it may be that old defined lines of demar- 

 cation will now have to be either remodelled or removed, since certain 

 transition periods may be shown to prove a continuity of the geological record. 

 Thus all such " Passage Beds " may in fact be connecting links between one 

 great geological period and another, rather than breaks in the continuity of 

 succession. 



Kote. — It is a curious fact deserving of notice, and which has not yet been fully ex- 

 plained, that in several instances at these points of junction between two great formations 

 there are those peculiar deposits called "Bone Beds," made up almost entirely of the com- 

 minuted remains of Saurian fish and Crustacea, the two latter only present in the older 

 Palasezoic rocks, as at the upper part of the Ludlow series, at the base of the Inferior 

 Oolite and Trias, and at the bottom of the Lower Green Sand. Saurian remains are at 

 present only known to occur in the Khostic bone bed. 



