Vol. 59.] TWO TOARCIAN AMMONITES. 463 



little doubt that, on the whole, the Author was correct as to what 

 he called the ' Toareian ' of Bredon Hill. The question was one as 

 to whether palaeontology or simple lithology was to be our guide in 

 the making of maps. The Author had often insisted on similar 

 points, and it was for the officers of the Geological Survey to reply 

 as best they could. But was not the Author slaying the slain in 

 his present onslaught? He had already proved that the so-called 

 ' Midford Sands ' were one thing in one place, and another thing in 

 another. In Gloucestershire the term ' Cotteswold Sands ' would 

 be more appropriate. The speaker admitted that it was some years 

 since he had worked at this subject, but as regards the position of 

 his ammonite-zones he had always found the Author correct. 



Mr. Whitaker, in regard to Bredon Hill, pointed out that the 

 Survey-work in that area was done 40 or 50 years ago, and a 

 Survey-map did not profess to theorize about fossil-zones, but to 

 constitute a record of lithological facts. No one in those days had 

 heard of ' Toareian,' or even of ' Midford Sands.' The section which 

 the Author built up from the Survey-map was not one that a 

 surveyor would have drawn. The Midford Sand of one place was 

 not necessarily the Midford Sand of another. 



The Rev. J. F. Blake remarked, with reference to the general 

 scheme of ammonite-development propounded by the Author, that 

 what with two series, an ascending and a descending one, and the 

 power assumed of skipping any stage or stages, it was not difficult 

 to fit any ammonite into such a scheme ; but the great majority of 

 ammonites had nothing to do with spines — and the theory would 

 make them all immature. In fact they completed their development 

 in many other ways — spines appeared to be only abundant at 

 certain epochs of the Earth's history — and a too exclusive attention 

 to the ammonites of any one such epoch might lead to the idea 

 that spines formed an essential feature in their development. For 

 the rest, the early and late stages of smoothness and lineation were 

 nothing but the natural concomitants of youth and age, as witnessed 

 even in human beings. 



With regard to the mapping criticized in the other paper, the 

 speaker yielded to no one in his appreciation of the importance 

 of palaeontological zones ; but where these were said to be 

 non-coincident with the boundaries of strata of particular litho- 

 logical character, two courses were open — they might map the 

 zones, and describe the changes of lithology ; or they might map 

 the strata, and describe the zones. The latter course he would 

 prefer, as giving more scope for details on the more important subject. 

 But they must remember that the Geological Survey based its justi- 

 fication on the economical importance of its work, and not upon its 

 discrimination of zones, and it was hard that they should be blamed 

 for doing their duty by their paymasters. 



Dr. F. A. Bather accepted the previous speaker's comparison of 

 the stages of ammonite-growth and decline to those shown by the 

 human hair, and his statement that they were equally natural. 

 But if so, how could they be of no value in deciphering the history 



