ODLING : CORRELATION OF THE UPPER AND MIDDLE OOLITES 275 
Above the BenclifE Giits, and passing up from them, cccurs the 
Upper Corallian, consisting of the Osmington Oolite and Trigonia Beds. 
Further inland a true Coral Rag facies — i.e., a facies replete with numer- 
ous corals such as Isastroea, Thamnastroea and Thecosmilia occurs, but 
this facies does not appear to exist in the coastal sections, except in the 
Supra Corallian ot Ringstead Bay as stated below. 
Succeeding the Trigonia Beds there occurs a series of remarkable 
passage beds from the Corallian into the Kimeridge Clay, consisting 
of sandstones and sandy limestones alternating with clays, the hard 
beds having a Corallian fauna, whilst the intervening clays are full of 
specimens of Ostrea deltoidea, a typical Lower Kimeridge form. 
These passage beds are best seen in the cliff section near Sandsfoot 
Castle, w^est of Weymouth, but the uppermost two beds only occur in 
Ringstead Bay, east of Weymouth, and the highest Corallian facies, 
the Abbot sbury Iron Ore in the neighbourhood of Abbotsbury is well 
up in the Kimeridge Clay as mentioned above. The struggle for 
existence of the two facies (Corallian and Kimeridgian) is so remark- 
able that it seems desirable to record the complete sequence here. It 
is to be noticed that although Ostrea deltoidea occurs in the arenaceous 
beds, it is almost the only fossil in the clays, especially in the base where 
the lowest specimens are attached to the sandstones. To this series 
Hudleston has aptly given the name of Supra-Corallian, which includes 
the Kimeridge Grit of Damon. 
SECTION OF SUPRA-CORALLIAN IN THE WEYMOUTH DISTRICT 
(excluding THE ABBOTSBURY IRON ORE). 
i 6. — Gritty Limestone (Kimeridge Giit of Damon), with 
gjg^^-J Thamnastroea, Thecosmilia, Stylina, Exogyra nana. 
Oh 
-O 4J 
Ctenostreon prchoscideum, Cidaris florigemma, etc. 
5. — Blue Clay with Ostrea deltoidea. 
§ -j 4. — Ferruginous sands with Ostrea deltoidea and Ctenos- 
treon prohoscideum. 
3. — Blue Clay with Ostrea deltoidea. 
-g I 2. — Ferruginous sandstone with Ostrea deltoidea, Pecten 
^ O ] vagans, Pecten episcopalis. 
[ 1. — Blue Clay with Ostrea deltoidea and A tarte sp. 
Corallian Trijcnia Beds. 
