42 



TYPE AMMONITES— IV 



Mar. 



there are many non-sequences. So that a time-interval of over 500 to 



perhaps 1,000 feet of deposit may really separate certain Coralhan- 



Oxfordian beds which, in places, are almost or even quite in contact. 



Evidence in regard to Nos. 1-14 is given in Seqq. X — XV following. 



Sequence X — Port an Righ, Scotland 

 Port an Righ, Balintore, Ross. Specimens found loose on shore 



Correlation 



Rasenian 



bay lei 

 Prionodoceratan 



prionodes 



dichotomum 

 Cf. Seq. VIII, 5 



Strata 

 Round nodules 



Eauna 



Pidonia cf. parva, Torn- 

 quist 



Prionodoceras aff. serra- 

 tiim and several other 

 spp. 



Dichotomoceras aff. dicho- 

 tomum 



Amoebocerates compar- 

 able with earliest N. 

 Ferriby specimens 



The point here is the association of Prionodoceras and Pidonia 

 with the confirmation given to Sequence \TII in regard to Dichotomoceras. 

 That genus cannot, as I supposed, belong to the Perisphinctean 

 (Argovian), PI. CXXXIX ; its locality was correctly given as Oxford, 

 that is, Shotover ; and it is not a species of the Ampthill Clay, like as it is 

 to several of them. According to the evidence of this Scottish locality, 

 Dichotomoceras, Prionodoceras and Pidonia are associated : according to 

 Seq. ^TII, p. 39, Dichotomoceras is a few feet lower than Prionodoceras. 



Sequence XI — Wester Gartv, Scotland 

 Correlation Strata and Localities Eauna 



Doubtful 



Rasenian 



kitchini 



stephanoides 



desmonotiis ? 

 kitchini 



1. Calcareous Sandstone — 



Shore 560 yards N.E. of 

 Sron Rudha na Gaoithe, 

 Wester Garty, Helmsdale 



2. Shales [and sandstone] — • 



Sliore 600 yards N.E. 

 etc. 



3. Shales — Shore 1,130 



yards N.E. etc. 



4. Calcareous Sandstone — 



Shore 1246 yards N.E. 

 etc. [A repetition of 

 No. I ?1 



Physodoceras cf. nni- 

 spinosus ; Rhynchonella 

 stitherlandi, Terehratitla 

 joassi 



Amoeboceras cf. kitchini; 

 Amoeb. cf. pingue [in 

 sandstone] 



Amoeb. cf. kitchini ; 

 Rasenia cf. stephan- 

 oides 



Rasenia cf. striolaris ; 

 Rh. sutherlandi, A moeb. 

 cf. kitchini 



