Vol. 69.] DERIVED CEPHALOPODA OF THE 110LDERXESS DRIET. 17 L 



derivative specimens of Psiloceras submitted to Mr. Buckman, he 

 has identified the following : — 



Psiloceras cf.brevicellatum Pompeckj. j Psiloceras cf. plicatum (Quenst.). 



Ps. erugatum (Bean-Phillips). Ps. provinciate ? (Querist.). 



Ps. erugatum ? (Bean-Phillips). Ps. cf. psilonotum (Quenst.). 



Ps. cf. lave (Quenst.). | Psiloceras sp. nov. 



This list implies that there is much careful work still to be 

 done on this genus, and that English lists will receive some addition 

 to their scanty tale of two. 



It is of interest to observe that Psiloceras provinciate (? ) and the 

 new species are very similar to several figured by Dr. F. Wakner l 

 and recorded as occurring in a yellowish-grey limestone, together 

 with Wcehneroceras megastoma, at Schreinbach. They are, therefore, 

 of a later age than Ps. plan orbis itself. Our specimens differ in 

 having somewhat less complicated suture-lines. The Schreinbach 

 forms possess very much foliated suture-lines, and the whorls are 

 more inflated. 



In our own collection there are more examples of Ps. erugatum 

 than of any other form. Other collectors, however, possess more 

 specimens of the Ps. Iceve type, which I believe are very similar to, if 

 not identical with, the German type styled Ps. la;ve. 



The matrix of the specimens is generally a crystalline shelly 

 limestone, but in a few cases a tough fine-grained earthy one. 

 The colour of the rock is usually pale grey, sometimes it has a 

 brownish tinge. As in Tate & Make's time, so now, there is no 

 locality in Yorkshire where these limestones can be seen in place. 



It is evident from the character of these lowest limestones that, 

 although they do not indicate a deep sea, they do indicate a clear 

 one, free, or nearly free, from the dark mud of the succeeding zones. 

 This may indicate either remoteness from the coast-line of the time, 

 or the absence of mud-bearing currents. 



Caloceras Beds. 



On the Continent, between the Planorbis Zone and that of 

 Schlotheimia angulata, there is a so-called 'Caloceras Bed,' but this 

 bed has never yet been identified in Yorkshire. In the Drift, 

 however, many specimens are found of the genus Caloceras with 

 fairly stout whorls, which may at present be collected under the 

 specific names of C. johnstoni (Sow.) and C. belcheri (Simpson). 



The specimens of this series (with one exception) have not been 

 submitted to Mr. Buckman ; but, from the varying suture-lines 

 and ornamentation, I am impelled to the conclusion that there are 

 more than two species in the Boulder Clay. Most of the specimens 

 are beautiful casts in calcite. The matrices are all hard limestones, 

 and no other ammonite has yet been found associated with them 

 in the same block. As a rule, there is no other fossil visible in 

 the boulder. 



1 ' Zonen des Unteren Lias ' Beitr. Pal. (Esterr.-Ung. vol. iii (1884) pi. xxiii 

 (xi) figs. 6a & la. 



