TV. R. Eudkston—The Yorkshire Oolite. 129 



Fig. le. Portion of same magnified. 



,, 3. Tkurotomaria reticulata, Sowerby. Coral Eag of Settrington Grange. My 



Collection. 



,, 4a and 5. ,, Agassizii, Miinster. Coral Rag of N. Grimston. Strick- 

 land Collection. Eack and front. 



,, 5. Pafe^^a rM^osa, Sowerby, variety. Coral Eag of N. Grimston. Strickland 



Collection. 



,, %. Bulla Beaugrnndi. De Loriol. Coral Eag of Ay ton. My Collection. 



,, 7. Act (BOH retusus, Phillips. Coral Eag of Ayton. Leckenby Collection. 



,, 8. Ci/lmdrites elongatus, Phillips. Passage-beds of the Lower Limestones, 



Scarborough Castle. My Collection. 



,, 9. Gi/linch-ites, s-^. Coral Eag of Ayton. My Collection. 



Explanation of Table. 



The table annexed contains a complete list of the Gasteropoda 

 entitled to be regarded as species belonging to the CoralHan beds in 

 Yoi'kshire. On referring to the generalized scheme of these beds in 

 the special introduction, pp. 246 — 247, the various subdivisions are 

 indicated, but a few additional remarks explanatory of the four 

 columns in the table of fossils may be useful. 



The basal beds of the Kimmeridge Clay limit the group upwards. 

 The Supracoralline beds, which immediately underlie these, have 

 hitherto yielded such very poor traces of Univalves, that it is not 

 worth while to devote a column to this subformation. 



O.K. No. 2. — This is the Florigemma-Hag, which girdles the 

 western half of the Vale of Pickering, and overlies the Coralline 

 Oolite of those regions. North Grimston, Langton Wold, Hildenley, 

 Slingsby, etc., have been the most productive localities. Its fauna 

 is fairly similar to that of CK. No. 1 ; but where the forms are 

 identical or analogous, they are for the most part finer and larger. 

 Its affinities with the fauna of the Coral Kag at Upware ai'e rather 

 striking — shown perhaps still more in the Conchifera. 



O.K. No. 1. — This is the Coral Rag which occupies the inner 

 slopes flanking the Vale of Pickering eastwards from Brompton. 

 Seamer station is the nearest point to Scarborough, distant about three 

 miles. Brompton, Ruston, Ayton and Seamer are the best places 

 for collecting ; and as all these villages are within an easy drive of 

 Scarborough, that town is often quoted as the locality for the fossils 

 of this Rag. It is devoid of Gidaris florigemma, but contains Oid. 

 SmitMi} 



CO. — The Coralline Oolite includes the ChemnitrAa-Wvae^ionQS, 

 and calcareous pastes with Oolite which underlie the Coital Rags 

 throughout the circuit of the Vale. The Oolite at Malton belongs 

 here. PalEeontologically it includes the shell-beds connected with 

 the Middle Calcareous Grit, especially the Trigonia-heAs at Pickering. 

 The subdivision contains a large and varied assemblage of Conchi- 

 fera, but the Gasteropoda, though individually abundant in some 

 instances, belong to few species. 



L.L. — The Lower Limestones constitute an important group or 

 subformation in a stratigraphical sense, and they contain lai'ge beds 



' There may be some doubt as to whether all the spines of Cidaris — for the test is 

 hardly ever met with — really belong to C. Smithii, "Wright, but no spine which could 

 fairly be refen-ed to C. florigemma has been found. 



DECADE II. — VOL. VIH. — NO. III. 9 



