98 M.K. HOWARTH 



Zone of Prodactylioceras davoei 

 Subzone of Aegoceras (Oistoceras) figulinum 



600.5 Shale, silty, pale grey 0.36 



600.4 Limestone nodules (= bed v of Howarth, 1955: 155) 0.06 



Aegoceras (Oistoceras) figulinum (Simpson) (1 1; SM J35968, SM J44776-85). 



600.3 Shale, silty 0.91 



600.2 Limestone, sideritic, forming a continuous bed (= bed iii of Howarth, 1955: 155) 0.18 



Aegoceras (Oistoceras) angulatum (Quenstedt) (9; SM J44790, CA 4595-4602). 



600.1 Shale, silty 0.15 



599 Sandstone, flaggy, with ripple marks and oyster bands; the top surface forms the floor of Castle Chamber (= bed i of 



Howarth, 1955: 155) 1.42 



Aegoceras (Oistoceras) angulatum (Quenstedt) (1; SM J44789) 



598.35 Shale, silty, laminated 0.33 



598.34 Limestone nodules 0.08 



598.33 Shale, silty, laminated 1.00 



598.32 Limestone, grey, weathering yellow; forms continuous tabular bed 0.10 



598.31 Shale, silty, soft, but harder near top 2.79 



598.2 Shale, silty, hard; forms a conspicuous feature in the cliff and on the scar 0.15 



598.1 Shale, silty, soft, darker than the two beds above; occasional sideritic mudstone nodules in middle and upper part 0.67 



Aegoceras (Oistoceras) sinuosiforme Spath (5; C.38930, C.39556, C.39579, CA 4594; PI. 7, fig. 14). 



597 Limestone nodules 0.13 



Aegoceras (Oistoceras) sinuosiforme Spath (42; C.39398, C.39418-36 [C.39421/22 and C. 39429/30 are single 

 specimens], C.39499-39502, C.39505-07, C.39561, C.39568-77, CA 4588-93). 



596.3 Shale, silty, with 0.09 m thick limestone nodules, especially in a band 0.3m below the top 1.22 



Aegoceras (Oistoceras) sinuosiforme Spath (28; C.39396-97, C.39399-39417, C.39437-38, C.39504, C.39549, 



C.39559, CA 4586-87), Liparoceras (L.) divaricosta (Trueman) (1; C.39455; PI. 8, fig. 1). 



596.2 Hard, calcified shale, with occasional sideritic mudstone nodules 0.15 



Aegocras (Oistoceras) sinuosiforme Spath (18; C.39503, C.39508-10. C.39560, C.39562-67, C.39578. CA 4580-85). 



Subzone of Aegoceras (A.) capricornus 



596.1 Shale, soft; occasional calcareous mudstone nodules 0.85 



595.2 Shale, silty, lower half soft, upper half harder; some lenses of oysters 0.56 



595.1 Scattered calcareous mudstone nodules in hard silty shale 0.10 



594 Shale, silty, with a few calcareous mudstone nodules 0.61 



Aegoceras (A.) lataecosta (J. de C. Sowerby) (1, lost), Aegoceras (A.) sp. indet. (10; CA 4579). 

 593 Sideritic mudstone nodules; conspicuous on the scars at Bulmer Steel Hole 0.13 



Aegoceras (A.) artigyrus (Brown) (4; CA 4604). 



592 Shale, silty, laminated with some hard bands; a few sideritic mudstone nodules 0.61 



591 The Oyster Bed. Hard, silty shale, with flat sideritic mudstone nodules; many oysters and other bivalves 0.18 



Aegoceras (A.) lataecosta (J. de C. Sowerby) (1; C. 39395). 



REDCAR MUDSTONE FORMATION 

 IRONSTONE SHALE MEMBER 



Subzone of Aegoceras (A.) maculatum 



590.7 Shale, silty 1.42 



590.66 Spherical sideritic mudstone nodules 0.10 



590.65 Shale, silty, with scattered sideritic mudstone nodules 0.23 



590.64 Sideritic mudstone nodules 0.08 



590.63 Shale, silty, with scattered sideritic mudstone nodules near the base 0.20 



Aegoceras (A.) maculatum (Young & Bird) (8; C.38881. C.38886-90, C.38893, CA 4578), Aegoceras (A.) maculatum 



(Young & Bird) var. leckenbyi Spath ( 1 ; C.38880). 



590.62 Shale, silty 0.41 



590.61 Shale, silty, with many sideritic mudstone nodules 0.46 



Aegoceras (A.) maculatum (Young & Bird) (8; C.38882-85, C.38891-92, C.38894, C.38896; PL 7, fig. 13). 



590.5 Shale, silty 1.30 



590.43 Shale, silty, with a few sideritic mudstone nodules near the top 0.23 



590.42 Calcareous mudstone nodules 0.08 



590.41 Shale, silty, with a few sideritic mudstone nodules near the base 0.20 



590.3 Shale, silty, with occasional very large (up to 1 m diameter) sideritic mudstone nodules 0.5-1.5 m below the top; seen 



on the scar on the south side of Bulmer Steel Hole 3.58 



