712 MESSES. S. S. BUCKMAN AND E. WILSON [Nov. 1896, 



hemera in date ; but in other cases pockets of later deposits have 

 been left to tell the tale of what was once laid down there. We 

 visited the section and made the following observations, which may 

 be of interest for comparison with Maes Knoll : — 



Section XI. — Wellow. First cutting on the Somerset and 

 Dorset Railway towards Radstock. 



ft. ins. ft. ins. 

 1. Cream-coloured, crystalline, coarse- 

 grained limestone, Terebratulaglobata 

 (Cotteswold type), about 5 feet up. 

 Several feet thick. 

 GARANTiANiE. 2. Yellowish, very strongly ironshot stone, 

 the grains not so large as in bed 5. 

 Acanthothyris spinosa, Nerinma Guisei. 

 Small Asiarte and lamellibranchs ... 4 

 3. Hard iron-specked limestone witb iron 

 markings, irregularly but firmly 



cemented to bed below 2 



6 



Dumortieri^e ? 4. A greenish-pink, arenaceous stone, 

 from 1 to 3 inches in thickness, much 



bored by Lithodomi 3 



Dispansi ? 5. Yellowish, very strongly ironshot stone, 

 to Bifrontis. Hildoceras bifrons, Grammoceras 



doerntense 2 



6. Ironshot, bluish-grey limestone with 

 Hildoceras bifrons, Dactylioceras, 

 Bhynchonella cf. Moorei 4 



Falciferi. 7. Pinkish, argillaceous stone with iron 

 specks containing ammonites indi- 

 cative of the falciferum and perhaps 



bifrons horizons 8 



8. Blue clay, visible in the next cutting 



towards Radstock x about 20 



At the place where the section was measured Beds 3 & 4 were 

 not found, so that Beds 2 & 5, both remarkable ironshot beds, came 

 into actual contact, with the result that the same block of stone, only 

 a few inches thick, yielded Hildoceras bifrons and Acanthothyris 

 spinosa. The statement that these two species occurred together 

 would have been deemed incredible, although it is true enough in 

 the present case. Their occurrence together does not, however, prove 

 that they were contemporaneous ; yet such a supposition has led 

 to much futile argument about inosculation of zones. Beally the 

 explanation in this case is simple. It is known from the evidence of 

 many other localities that an immense interval of time must have 

 elapsed between the existence of Hildoceras bifrons and the time 

 when Acanthothyris spinosa lived. Therefore whatever deposit 

 accumulated above the bed with Hildoceras bifrons must have been 

 removed down to that level before the deposit of the Acanthothyris- 

 spinosa date was laid down. That there was such removal is shown 

 in parts of this cutting, for, as stated above, the full sequence was 



1 There is no evidence a&to the date, but presumably this is the same clay as 

 that proved at Maes Knoll, Section VII b, No. 17, 



