16 TYPE AMMONITES— VII 



EDITORIAL NOTE 



BY 

 A. MORLEY DAVIES. 



The germ of " Type Ammonites " may be found in a letter from 

 the author to the Geological Magazine of August, 1904, asking for 

 information on the types of S. P. Pratt and of Young & Bird, for the 

 purposes of the Pal^ontologia Universalis, to which he was at this 

 time contributing in respect of English ammonites. It may be presumed 

 that, as a result of this letter, he discovered the large series of types 

 in the Whitby Museum, and eventually decided that a separate publica- 

 tion was preferable. 



The original format of Yorkshire Type Ammonites seems to have 

 been largely influenced by that of the Pal^eontologia Universalis. 

 Apart from the inclusion of a general text on bibliographic, classificatory 

 and chronological subjects, the main difference was the absence of a 

 reproduction of the original figure (in the case of Simpson's species 

 non-existent) and the printing of the original description and " Remarks " 

 in wrapper form, bearing on the outside the number, original name and 

 modern generic name of the species figured. But the unit for numerical 

 purposes was still the original species of the early author, not the species 

 as recognized by the modern reviser. Hence arose some anomalies in 

 numbering referred to below. 



Towards the end of Volume II, completed in 1918, after a break 

 of nearly four years due to the War, drastic alterations were introduced. 

 The wrapper-text was replaced by a greatly-abbreviated description on 

 the plate itself, and the limitations to Yorkshire (already broken in 

 Nos. 37, 81, and 97) and to species already named (half-broken in the 

 case of Nos. 42, 91, 104) were abandoned. With the opening of Vol. Ill 

 was also abandoned the separate pagination of classificatory, chrono- 

 logical and other text. 



The issue of plates with wrapper-text was continued up to No. 121, 

 but plates of the new style, numbered 122 to 130, were issued con- 

 currently with the last of the old style during 1918-19 (Vol. II), 

 leading to some irregularity in the numerical sequence. 



The divergence of plan from that of ~P alceontologia Universalis was 

 now very wide, yet among the new features was the occasional repro- 

 duction of an original figure (protograph), in very special cases only 

 (PI. 131a, 138a, 199a, 337, 392, 393, 504, 539, 540, 608, 673, 789 and 

 in the original issue of PL 537, but not in the plate afterwards substituted). 



As the " shorthand ' description on the new-style plates appears 

 not to be always understood, some examples may be analysed here. 



Plate CCCLXII. 



Macrocephalites macrocephalus. 



" Peterborough ; Cornbrash " ; [Oeschingen, Wurtemberg ; 



Callovian] Test limonite ; matrix, blue and brown, ironshot ; J.W.T. Coll. 



S. 44, 48, 50, 16 ? ; 62, 52, 45, 15 ; size 68 ; max. c. 120. 



TMETOKEPHALITES BATHYTMETUS, nov. 

 Macrocephalitan, Macrocephalites ; Genotype, Holotype. Cf. CCCLXXII. 



The name first given, in small caps, is either that with which the 

 specimen is actually labelled or that which is likely to be given to this 



