432 ME. s. j^. ErcKMAX ox [vol. Ixxviii,. 



grains, lower it Las grains which are noticeably pink ; at a still . 

 lower level, which I dated as sauzei^ are the green grains. 



The point is of considerable importance for dating specimens.- 

 In the 'seventies (at the time, I understand, when the road-cutting- 

 was made at Milborne Wick), \evy extensive collections of fossils- 

 were obtained from this place : many are in my collection, and it is- 

 rare to see a public or private collection without noting fossils- 

 which have the characteristic Milborne- Wick matrices. If my 

 observations are correct, the lithic differences afford a means of 

 ascertaining the sequence of these fossils. I have examined many 

 ammonites in m}^ collection, and they certainly tend to confirm 

 this opinion. The very common fossil of the hlagdeni zone is 

 Po&cilomorplius cycJoides — common, because the name really covers 

 a multitude of different forms; but Mr. Eichardson does not 

 mention this species. 



Not onl}^ is he incorrect in citing m}'' authority for this dating o£ 

 the marl with green grains ; but I think that he may be incorrect 

 in his dating of the beds which he saw. My ' Bed 2 ' is given by 

 me as 4 inches thick, and Beds 3 & 4, as 1 foot, total = 16 inches. 

 Mr. Bichardson's Beds 2 to 4 total 13 inches. So on that basis he- 

 may have hit a place Avhere Bed 2 Avas only 1 inch thick. But 

 there is a lack of 14 inches in the rest of his section — under Bed 6. 

 I think it possible that \Yhere he took his section he saw, at the 

 top. Bed 5 — where I noted the green grains — with just some small 

 portions of the bigher beds and their fossils in more or less derived 

 condition mixed up with the disturbed green-grained marl. This 

 point might be settled by an examination of the matrix inside 

 the fossils, not that outside. 



There are two further points for consideration : — 



That in this section local removal of the beds below the non- 

 sequence — Beds 2-Ai — is possible, with the corollary that, at 

 favourable places. Bed 2 may be thicker than is recorded in my 

 section ; and that there may be local variation in the thickness of 

 any of the beds. Therefore, if Mr. Richardson found green-grained 

 rock at the top of the section, whereas I found it at 10 inches below,, 

 the explanation maybe local thickening at the top of Bed 5 and/or 

 local denudation. 



One point I would add about this section, from examination of 

 ammonites from old collections — specimens of IVitcJieJJia show a 

 matrix with green grains and Asfarte sjnssa ; wherefore it is 

 possible that the top of Bed 5 should be reckoned as 7FzYc/^(°///« 

 and not as sauzei, as it is in my paper.^ Actuall}^ I cannot recollect 

 ^ any example of ^Ammonites sauzei'' (Ofoites) from Milborne 

 Wick. The species ' Spliceroceras perexpansum'' (Lahyrintlio- 

 ceras) - cited for Bed 4 may really indicate a somewhat different 

 date. But whether just before or just after cannot be said 3"et : this, 

 is a matter possibly to be considered in future faunal analyses. 



1 I, 3, p. 503. 



^' I, 8, pt. 19, jdIs. cxxxiv & cxxxy. 



