196 ME. G. W. LAMPLTJGH ON THE SPEETON SEEIES [Ma) 7 1896, 



instances is the species stated, the remainder giving the genus alone. 

 Moreover a footnote is added to the lists expressing great hesitancy 

 in the identifications. The following are the fossils mentioned : — 



Sr-ECIES : Terebratula ovoides, Sby., Waldheimia Woodwardii, 

 Myacites recurva, Lucina portlandica, Sby., Thracia Phillipsii, 

 Roem. (or depressa, Sby.), Ammonites biplex, Sby., A. plicatilis, and 

 A. speetonensis, Y. & B. 



Geneka : Area, sp., Astarte, Cyprina, Oucullcea, sp., Isocardia ?, 

 Lima, sp., Pectunculus, sp., Trigonia, sp., Natica, sp., Pleurotomaria, 

 sp., Belemnites, sp. 



In discussing this list we may at once dismiss the genera, re- 

 marking only that the rotund form of the casts, the presence of the 

 impression of both valves in the case of bivalves, the absence of 

 fragments of oysters and other characteristic hard fossils occurring 

 abundantly in the underlying strata, and the general t'acies of the 

 assemblage, are all points which tell against the derivative origin of 

 the nodules. But when we turn to the consideration of the 

 species above-mentioned, we do not find any better evidence in 

 support of the statement that " there can be no doubt that most of 

 the phosphates have been derived from the Kimeridge Clay ' (' East 

 Lincolnshire,' p. 139). Terebratula ovoides, Sby., if it be the 

 species mentioned by Mr. W. Keeping, 1 has been found in blocks 

 supposed to have been derived from the Spilsby Sandstone, and 

 also in a phosphatized condition at Up ware, Brickhill, and Potton, 

 and therefore if the species be rightly determined the evidence is 

 entirely against its derivative character. Waldheimia Woodwardii, 

 Walker, is not known to exist in rocks of a lower horizon. Myacites 

 recurva is referred to at the foot of the list as being a form which 

 * might equally well be Panopaza neocomiensis ; and on the other 

 hand Thracia Phillipsii may well be Th. depressa of the Kimeridge 

 Clay.' Lucina portlandica occurs commonly at Speeton as a cast 

 in the i Coprolite-bed ' (Zone E), and appears to be confined to this 

 horizon both in Yorkshire and Lincolnshire. Ammonites biplex, as 

 the name is usually applied in England, is almost without deter- 

 minative value even when the specimens are well preserved, since 

 almost every round-whorled ammonite with bifurcating ribs, from 

 whatever horizon, has in turn received the title, whether it be 

 of the genus Perisphinctes or Olcostephanus or what not. In some 

 of our public collections, for example, specimens from the Upper 

 Kimeridge have been mixed with others undoubtedly from the 

 1 Zone of Ammonites speetonensis ' of the Speeton Clay under the 

 common name of A. biplex? A. speetonensis stauds in exactly 

 similar case, being a much-abused species into which it has been 

 the fashion of English palaeontologists to thrust almost any 

 form of the genus Olcostephanus that had the misfortune to be 

 found anywhere between the base of the Hed Chalk and the top of 



1 W. Keeping, ' Fossils of Upware, etc.,' Cambridge, 1883. pp. 34-37. 



2 See Quart. Jounu Oeol. Soc. vol. xlv. (1889) p. 613. The last-menfioned 

 form, Ammonites concinnus of Phillips, is recognized by Pavlow as including 

 Olcostephanus {Simbirskites) subinversus, M. Pavl., and other allied species. 



