708 MESSRS. S. S. BUCKHAtf AND E. WILSON [Nov. 1 896, 



called ; Sands ' at all — they are truly clay. These beds are un- 

 doubtedly the Upper Lias of some previous observers, while the 

 Terebratula Eudesi and concavum-beds were their ' Midford Sands.' 



As to the thickness of the strata of the Bumortierice hemera at 

 Dundry as compared with the Cotteswolds, we find the opposite 

 to what obtained in regard to the last comparison — the variabilis- 

 beds ; but it is not so pronounced. Dundry shows 50 to 60 feet, as 

 against the Cotteswold deposit, which is often only a few inches in 

 thickness, but does reach to as much as 8 feet at North Nibley. 



The sequence of ammonites found to obtain at Dundry Hill from 

 the time of bifrons to that of Dumortieria is just the same as that 

 which was first pointed out by one of us \ and has since been proved 

 over so large a part of Europe. 2 



(4) The Strata of Aalenian Age. 



At Dundry there is evidence, in a bluish stone at the base of the 

 so-called ' Inferior Oolite ' limestone, of a deposit containing ammo- 

 nites of the Grammoceras-acdense type, contemporaneous with 

 the upper part of the Cotteswold Cephalopod-bed. We have, how- 

 ever, no very definite evidence of any deposit during the opalini 

 hemera, nor during the scissi hemera, which is so noticeable in the 

 Cotteswolds as the " Sandy ferruginous limestone.'' 



At Dundry we have evidence of the deposit of rock during the 

 Murchisonce hemera, but we have little testimony as to any deposit 

 during the bradfordensis hemera ; this is partly owing to the want 

 of exposures and the intractable nature of the rock. The deposits 

 of the date of Murchisonce (and perhaps bradfordensis) are thin, 

 like the contemporaneous deposits in Dorset, whereas in the Cottes- 

 wolds the contemporaneous strata attain a very great thickness 

 (150 feet or more), and their subdivisions can be noted easily. 



(5) The Strata of Bajocian Age. 



The presence of the Sonninia Jissilobata-ovalis-type of ammonite 

 at once marks a certain horizon at Dundry as contemporaneous 



1 S. S. Buckman, ' On the Cotteswold, Midford, and Yeovil Sands,' Quart. 

 Journ. G-eol. Soc. vol. xlv. (1889) p. 440 ; extended and added to in ' Monograph 

 Inferior Ool. Ammonites,' Pal. Soc. vol. xliv. (1890) p. 164; and 'On the 

 Jurense Zone,' Journ. Northants Nat. Field Club, vol. vi. (1890), list of species 

 peculiar to the different divisions. 



2 Louis Brasil, ' Sur le Lias superieur et le Bajocien de Tilly-sur-Seulles et 

 Feuguerolles,' Bull, du Laboratoire de Geol. de la Faculte des Sciences de 

 Caen, vol. ii. p. 167, 1893 ; ' Les Divisions de la Zone a Lytoceras jurense en 

 Normandie,' Bull. Soc. Linn. Normandie, ser. 4, vol. ix. fasc. 1, p. 34,, 1896 ; 

 also ' Rernarques sur la Constitution du Toarcien superieur dans le Calvados,' 

 ibid. fasc. 2, p. 147, 1896. 



Emile Haug, « Jurassique,' La Grande Encyclopedic, p. 322, Paris, 1895. 



Jules Welsch, ' Sur la Succession des Faunes du Lias superieur et du Bajocien 

 inferieur dans le detroit du Poitou,' Compte-rendu de l'Academie des Sciences 

 de Poitiers, 1895. 



Chartron et Welsch, ' Sur la Succession, etc., dans les environs de Lugon 

 (Yendee)/ ibid. Aug. 1896. 



