Vol. 5 1.] OF THE MID-COTXESWOLDS. 419 



appellation suggests contemporaneous strata in Dorset and on the 

 Continent, known as Witchellia-beds. Concerning the Perna-bed 

 Wright says, 'It is probable likewise that the Perna-bed may repre- 

 sent a higher portion of the Upper Trigonia-grit than that exposed at 

 Leckbampton Hill ' ; and he gives it a thickness of 6 inches, below 

 4 feet of ragstone. 1 Dr. Wright discovered Terebratula Wrighti in 

 it, 2 and he also quotes Ammonites Eclouardianus therefrom. 3 The 

 same specimen as that here referred to is, probably, the one in my 

 cabinet now, purchased from his collection. It is not Edouardianus, 

 though closely resembling it. It is a somewhat latumbilicate 

 Witchellia, allied to Witchellia Sutneri (Branco). 



Wright's location of the ' Perna-bed,' as probably above the Upper 

 Trigonia-grit, was a mistake. The ammonites alone show this — 

 not only that it is really below the Upper Trigonia-grit, but that a 

 very considerable amount of time elapsed after the deposition of 

 the Perna-bed ( Witchellia-grit) and before the Upper Trigonia-grit 

 was laid down ; while during this time strata were being laid down 

 in other localities. 4 But, independently of any ammonites, the 

 Perna-bed ( Witchellia-grit) is actually below the Upper Trigonia- 

 grit by stratigraphical evidence. Again, it caps a freestone, and 

 the highest bed of this kind at present known in what is called 

 ' Inferior Oolite ' is the Notgrove Freestone. Further, the strati- 

 graphical position of this bed is shown by the sections described in 

 the present paper. 



The Witchellia-grit has been probably alluded to by my father in 

 the section of Lineover in the ' Geology of Cheltenham.' On p. 25 

 he notices a bed of argillaceous stone (No. 3) between the Trigonia- 

 and Gryphite-grits, from which he quotes a considerable series of 

 species (p. 27). The Ammonites Iceviusculus which he mentions is 

 very probably the specimen now in my cabinet — alluded to on p. 411 . 

 My father was right in the position he assigned to this bed, though 

 it is only part of what I place as Witchellia-grit. 



Part I. of this paper has shown that between Stroud and Leck- 

 hampton the highest bed upon which the Upper Trigonia-grit rests 

 is the Notgrove Freestone. Comparison with Dorset has proved 

 that even then strata deposited during certain hemerae are unre- 

 presented, so that the Upper Trigonia-grit rests non-sequentially 

 on the Xotgrove Freestone. The discovery of about 4 feet of 

 grits capping the Notgrove Freestone, and yielding ammonites 

 .(angustumbilicate Witchellice) is interesting in many respects ; it 

 slightly lessens the gap between the Upper Trigonia-grit and sub- 

 jacent beds ; it is noteworthy as an ammonitiferous deposit in a 

 district where ammonites of the -post-ojjalini hemerae are rare ; it 

 confirms in a satisfactory manner a surmise made in respect to the 

 chronology of Dorset strata. Thus, in correlating certain Dorset and 

 Gloucestershire strata in my previous paper (pp. 509-514), I stated 



1 ' Subdivisions of the Inferior Oolite,' Quart. Journ. Greol. Soc. vol. xvi. 

 .(1800) p. 42. 



3 Davidson, 'Jurassic Braehiopoda,' App. to vol. i. p. 20, Pal. Soc. 1854. 



3 Op. jam cit. p. 43. 



* Compare Table II., p. 422, and see Postscript, p. 461. 



