^, M. Brydone — Further Notes on the Trimmingham Chalk. 15 



this without reckoning in the thickness of the anomalous northern 

 part of the south bluff, which may fairly be quoted as not containing 

 0. lunata, as only one specimen has been found in it, and that very 

 dwarfed. But there are fossils which do occur throughout the 

 Trimmingham Chalk, yet, as far as I know, are confined to it, 

 such as Terebratulina gracilis, T. Gisei, Pentacrinus Agassizi, and 

 P. Bronni, to take well-marked and fairly plentiful forms. There 

 could be no hesitation in selecting as the zone-fossil Terebratulina 

 gracilis if it were not for the unfortunate but universal misapplica- 

 tion of this specific name to the characteristic fossil of the upper 

 zone of the Middle Chalk. T. Gisei, considered by itself as a possible 

 zone-fossil, is too small to be found with certainty, even if abundant, 

 and it is hardly that. But T. gracilis is such an ideal zone-fossil 

 that I propose to remove the objection to it stated above by 

 naming the Trimmingham Chalk " zone of Terebratulina gracilis 

 and T. Gisei," or, for familiar use, "zone of Terebratulina," it being 

 understood that T. Gisei is not conclusive when occurring by 

 itself, but that T. gracilis is. Pentacrinus Agassizi and P. Bronni 

 could, of course, be used to characterise a " zone of Pentacrinus," but 

 that would create great difficulty with the chalk of the erratics 

 between Overstrand and Sidestrand, a part of the cliff which is 

 unfortunately being ruined for geological observation by sloping 

 and path-making operations. Before the era of sloping set in these 

 erratics were about ten in number, and all (with one exception) 

 lay on a thick bed of boulder-clay, which ran with great regularity 

 at a practically unvarying height above the beach from the Overstrand 

 breakwater to the grounds of the new hotel at Sidestrand. My 

 attention was first drawn to these erratics by Miss Mary Townsend, 

 of Oatlands Park, Weybridge, who happened to be staying at 

 Overstrand in 1896, at a time when a storm had swept away the 

 sand on the beach and exposed a great number of chalk boulders, 

 no doubt all that had fallen from above for some years, I had 

 then just become keenly interested in the Chalk of the Norfolk 

 coast, and she, being aware of this, picked out for me all the fossils 

 she could with a penknife, including a perfect Micraster cor-anguinum 

 of the typical Norwich shape, a very creditable performance for 

 a lady with no previous experience of fossils and armed only with 

 a penknife. I have on several occasions been able to add to this 

 collection, the salient points of which are the presence of BhyncJionella 

 Beedensis, which occurs freely in the Cromer Chalk but not at all at 

 Trimmingham, and the abundance of a Pentacrinus which is neither 

 Agassizi nor Bronni, and does not occur either at Trimmingham or 

 in the Cromer Chalk. The occurrence of a Pentacrinus is a strong 

 link to the Trimmingham Chalk with its abundance of Pentacrinus, 

 and this association is strengthened by the character of the chalk 

 itself, which is often white, much mottled with blue-grey patches, 

 just like so much of the white chalk at Trimmingham, and it is 

 tempting to group this chalk with the Trimmingham Chalk rather 

 than with the Cromer Chalk. At the same time the presence of 

 B. Beedensis indicates that it is definitely older than the Trimmingham 



