67 



he says of the above, " A comparison, however, of the species of 

 Ammonites and other shells collected in these different localities 

 shows that, besides a similarity in lithological structure, there is 

 nothing in common between the strata ;"* and he accounts for the 

 appearances by supposing that the Ammonites Murchisona zone, by 

 thinning out, has brought the zone of Ammonites Humphresianus 

 into close relation with the sands of the Upper Lias.* 



As, however, the shells of the 2 feet 6 inches bed, described as 

 the Cephalopoda-bed at Bradford and other places in Dorset, are 

 identical with those at Dundry, and at both Bradford and Dundry 

 it contains with others 



Ammonites Parkinson!, Sow. (A. Ammonites Murchisonae, Sow. 



dorsetensis, Wr.J jurensis, Ziet. 

 Humphresianus, Sow. 



we conclude that the Cephalopoda-beds at Bradford and Dundry 

 are on the same horizon, and, further, that neither the one nor the 

 other has the slightest connexion with the Cephalopoda-bed of 

 Gloucestershire ; and, if this be so, the fact that the four Ammonites 

 just quoted have been made representatives of the four distinct 

 zones, will be a difficult problem to solve for those who implicitly 

 believe in zones. 



One of the more recent papers, "On the Correlation of the 

 several sub-divisions of the Inferior Oolite in the middle and south 

 of England," is by Dr. Holl, who concludes that the true position of 

 our Dorset and Somerset beds is higher in the series than is stated 

 by the geologists just quoted, and "that they are, in fact, the 

 southern extensions of the Upper and Lower Ragstones of Mr. Hull, 

 the uppermost of which is not represented in the typical section at 

 Leckhampton, having risen above the level of the country, and 

 cropped out before reaching the brow of the hills."t 



We agree with this view, except that we consider the Dorset 

 Cephalopoda-bed the equivalent of the Gryphite Grit at Leck- 

 hampton, and that the roughly bedded stone above is the repre- 

 sentative of the Trigonia Grit of Cold Comfort. The constant 

 presence of the same typical Ammonites on the top of Leck- 

 hampton Hill and in the Bradford Abbas quarries seems to prove 

 this assertion, such as 



* Quart. Journ. GeoL Soc., vol. xvi., p. 18. } Ibid., vol. xix. (1863), p. 307. 



