Geological Society. 151 



2. ' The Derived Cephalopoda of the Holderuess Drift.' 

 By Charles Thompson, B.Sc. 

 Although it has been known for a century that the Drift of 

 Ilolderness is rich in derived fossils, for many years the collecting 

 of them was neglected. However, in recent years, collections of 

 the cephalopoda have been made, and it is now claimed that about 

 a hundred and eighty species of ammonites are already in hand 

 from the Glacial Drift. There are two important points about 

 these specimens : the one, that a large number are new to York- 

 shire lists hitherto published ; the other, that the matrix of many 

 of them cannot be matched now by our land exposures. It remains 

 to consider whence they came. 



The whole of the Lower Lias is so well represented by all its 

 genera, and the rocky matrices are so characteristic, that it is urged 

 that the ice plucked them from outcrops in the bed of a former 

 North Sea; also that these outcrops show the continuity of the 

 North Yorkshire Basin with that of North- Western Germany. The 

 list appended to the paper supports this statement, for it shows that 

 many gaps are now filled, which are obvious when Hyatt's lists 

 for the two regions are compared. 



The Middle and the Upper Lias afford much material, but the 

 types are closer to those of North Yorkshire. The Oolites are very 

 scantily represented, although the Lower Cretaceous is abundantly 

 represented both by ammonites and by belemnites. Again, there is a 

 great difference between the state of preservation of a 'collection 

 made from the Drift, and that of one which can be made now from 

 the Speeton Clay in situ. Hence, the existence of a wide spread 

 of these clays to the east is confirmed. 



The Chalk belemnites belong to a zone higher than any known 

 Yorkshire : therefore, they probably came from the sea-bed. 



February oth, 1013.— Dr. Aubrey Strahan, F.B.S., President, 

 in the Chair. 



The following communication was read : — 



'On Two Deep Borings at Calvert Station (North Buckingham- 

 shire), and on the Palaeozoic Floor north of the Thames ' By 

 Arthur Morley Davies, A.R.C.S., D.Sc, F.G.S., and John PrinMo 

 H.M. Geological Survey. 



The two borings are about 370 yards apart in a due east-and- 



west direction. The eastern boring gives the following section :— 



Altitude of surface = about 290 O.D. 



., Thickness infect inches. 



b '" 1 4 o 



Oxford Olay — Ornatum Zone 93 3 



Non-seque nee. 

 Forest Marble go q 



Non-sequence. 

 Great Oolite ^n ^ 



Non-sequence. 

 Chipping Norton Limestones 7 a 



Non-sequence. 

 Lias— Domerian, Algovianum Zone to Oliar- 



niouthian, Jameaoni Zone i.>4u ,; 



U n c o n f o r m i t y. 

 Lower Tremadoc — Shineton Shales 954 g 



1398 



111 



