TYPE AMMONITES— III Mar. 



broader whorls and smaller umbilicus. Ribs about radial, mostly 

 trifurcate, with occasional additions, fading away on periphery. Geol. 

 Surv. Engl., 26106 ; Scarborough ; Kell. R. (c), grey oolite with pinkish 

 tinge, decomposing in places to ferruginous ; Holotype ; S. 57, 40, 27, 

 26 ; 68, 40, 27, 28 ; 21 ribs ; Li at 17 mm., 20/5 per cent. Tutcher Coll., 

 Chippenham ; K. Clay (c) ; a colomorph ; S. 53, 435, 28, 25 ; 18 ribs ; 

 Li at 22, 27 per cent. 



B. 2. Venter subgibbous. Max. c. 100 mm. +. 



P. koenigi, J. Sowerby sp. 1820 ; cclxiii, 3, Holotype ; F. 57, 38-5, 

 — - 3 2 '5> *7 ribs on last whorl ; " Charmouth [Dorset]," III, 113 ; loc. 

 not correct. Rampisham, Dorset, 13 miles N.E. by E. of Charmouth, 

 from which fine specimens of Proplanidites were obtained by Mr. D. S. 

 Darell, F.G.S., in similar lithic condition to Sowerby 's fig. 3, may well 

 be original locality. 



Geol. Surv. Engl., ex Darell Coll., 7688, Rampisham, Dorset ; 

 K. Clay (a) ; Topotype ? S. 57, 41, 33 (30), 30 ; 18 ribs ; specimen, 

 66 mm. full ; 17 ribs ; max. c. 108 mm. Li at 17, 31 per cent. G.S.E., 

 ex Hudleston Coll., No. 30774, Chippenham, Wilts ; K. Clay (a) ; S. 109, 

 41, 30, 28-5 ; 15 ribs ; Li at 26 - 5, 30 per cent. ; about one whorl body-ch. ; 

 max. c. 130. A mutation ? G.S.E., 30537, Weymouth, Dorset ; 

 K. Clay (b), black (nodule from clay) ; S. 67-5, 38, 29-5 ? 31 ; 16 ribs 

 to 57 mm. ; Li at 2i'5, 32^5 per cent. 



C. Nomomorphs ; s.l. degenerate ; Li, c. 25 per cent. 1. Venter 

 subgibbous, smooth. Max. c. 130 mm. +. 



P. laboratus, nov. Coarsely ornate ; 17 ribs ; somewhat stout 

 periphery ; indication of expanding umbilicus ; very like Perisph. 

 konighi, Neumayr, = P. majesticus, but umbilicus beginning to be 

 excentric, periphery more obtuse, s.l. simple. Geol. Surv. Engl., ex 

 Darell Coll., 7685, Rampisham, Dorset ; K. Clay (a) ; S. 71, 39, 31, 34 ; 

 117, 37, 28, 37 ; about one whorl body-ch., mark as if body-ch. continued 

 for another whorl ; max. = ij whorl body-ch. = c. 130 ; Li at 28, 

 c. 23 per cent. 



P. fabricatus, nov. Like P. laboratus, but not quite so stout ; 

 umbilicus wider and more excentric. Tutcher Coll., [Chippenham] ; 

 K. Clay (a) ; S. 71, 38, 29, 42 ; max. c. 95. 



P. involutus, nov. Cf. Per. konighi, Neum., xi, 3, but periphery 

 more obtuse. Whorls broader, umbilicus more excentric than .1. koenigi. 

 Sow. Morphic equivalent of P. laevigatas, but has degenerate s.l. 

 Geol. Surv. Engl., 30531 ; Holotype ; Chippenham, Wiltshire ; black ; 

 S. 57, 44, 28, 26 ; 92, 39, 28, 30; 15 ribs to 57 mm. diam., 18 ribs to 

 92 mm. -.Li, at 2i"5, 26 per cent. No. 7692, Rampisham, Dorset; 

 S. 107, 40, 28, 30 ; 14 ribs ; signs of becoming smooth ; body-ch. showing 

 nearly a whorl, its mark certainly another half-whorl = body-ch. 1 \ 

 whorl + = max. c. 140 mm. + ; mark continued around whorl, perhaps 

 colour-band ; No. 30538, Wilts ; Li at 21, 26 percent. ; 30527, Chippen- 

 ham ; S. 65, 415, 28, 275; 13 ribs; Li at 23. 25 percent.; all Kell. 

 Clay (b). " 



P. lentus, nov. A thinner development of P. involutus, with 

 more numerous smaller ribs, and with umbilicus beginning to open out 

 at a small diameter. Geol. Surv. Engl. 26092 ; Holotype ; Kellaways, 

 Wilts ; Kell. Rock (d) ; S. 69, 40, 25-5, 30 ; 20 ribs to 57 mm. diam. ; 

 19 ribs to 69 mm. ; max. c. 130 ; Li at 25, 20 per cent. 



C. 2. Venter subcuneate ; a. laterally costate (secondary ribs 

 strong). 



