G4 On the beds of Head on Hill and Golwell Bay. [Dec. G, 1880. 



one-fifth of those occurring at Brockenhurst, Colwell Bay, and 

 White Cliff are found at Barton." It would be certainly ano- 

 malous if the Venus-bed had more Barton forms than the Brocken- 

 hurst one, seeing that the former occupies a higher zone in the 

 Middle Headon series. 



An analysis is made of Prof. Judd's lists from which it appears 

 that in the one list are nine species said to pass into Barton beds, 

 while in the other list, these identical species have that range 

 denied to them. Again, in his Brockenhurst and Colwell Bay 

 list are 22 species of which the range into Barton beds is not 

 recognized, while an examination of the Edward's collection in 

 the British Museum shows that they pass up from Barton or 

 Brucklesham beds. 



From the authors' lists it appears, on the other hand, that the 

 percentage of Barton forms in the Whitley Ridge bed is about 

 42 per cent., a lower proportion than at White Cliff, because of 

 the number of corals special to the locality. At White Cliff Bay 

 this bed has 52 per cent. The proportion of Barton forms from 

 all the Brockenhurst localities, including the Roydon Zone, is 48 

 per cent. If for comparison the percentage of Barton forms in 

 the Middle Headon of Headon Hill is calculated, it is found to be 

 29 per cent. Fossil evidence leads therefore to the conclusion 

 that the Headon Hill marine bed is later in age than the Brocken- 

 hurst, the proportion of Barton forms in the latter being not 

 one fifth, but nearly one half — a result in accordance with their 

 strati graphical position. 



Similarly, to test by fossil evidence whether the Colwell Bay 

 bed is nearer related to the Brockenhurst than is the Headon 

 Hill one, the percentage of Barton forms is observed in each ; in 

 Colwell Bay, they were 20 per cent., in the Headon Hill bed also 

 29 per cent., while in the Brockenhurst bed they were 48 per cent. 



In order to complete the proof from fossils, if any such were 

 needed, it is noted that there are only two species in each case 

 common to either Colwell Bay, or Headon Hill, and Brockenhurst, 

 and not occurring at the other locality, while there are 2G species 

 common to Colwell Bay and Headon Hill, and not occurring at 

 Brockenhurst. 



These results are in perfect accordance with the stratigraphical 

 succession, and show that Prof. Judd has misconceived the position 

 of the Brockenhurst bed. The authors therefore reject his pro- 

 posed term of " Brockenhurst series," and revert to the classifica- 

 tion and nomenclature of the Geological Survey. 



