142 LIASSIC OPHIURIDiE. 



Section of the Marlstone at RockcUff, near Staithes. (See p. 143.) 



No. 



2 

 3 



4 

 5 

 6 

 7 

 8 

 9 



10 

 11 



12 



LiTHOLOGY. 



Jet Rock. 

 Lower part of the Upper Lias. 



Marlstone Beds. 



Total thickness of the series . 

 subdivided into — 



Main Ironstone Bands. 



Connected blocks of hard ironstone, a foot 

 and upwards in thickness, with thin 

 seams of intervening shale. 



Sandy shale. 



Iron dogger. 



Sandy shale. 

 Iron dogger. 

 Sandy shale. 

 Iron dogger. 

 Sandy shale. 



Iron dogger. 



Shaley sandstone. 



Alternations of calcareous sandstone and 

 sandy shale, generally one sandstone 

 bed alternating with a similar bed ; 

 the seams covered with fossils. 



Thick- 

 ness. 



Shaley marlstone. 



13 Shaley sandstone, gradually partaking of 

 the nature of Lower Lias shale. 



Lower Lias Shale. 

 Thickness above the level of the sea . 



Feet. 



50 



160 



25 



10 

 15 



18 



10 

 40 



20 



Organic Remains. 



Saurians, Fish, Cephalopoda. 



Terebratula trilineata, Y. and B. 

 punctata, Sow. ; very abundant. 



= T. 



150 



Ammonites Clevelandieus, Y. and B. = A. 

 margaritatus, Montf. 



J 



Am. margaritatus =: A. vittatus, Y. and B. 



Belemnites paxillosus, Schloth ., Pholadomya 

 obliquata, Phil., Modiola scalprum, Sow., 

 Lima Hermanni, Voltz., Opkioderma 

 Milleri, Phil., Ophioderma carinata, Wr., 

 Ammonites capricornus, Sch. ^A. 7nacu- 

 latus, Y., Avicula incequivalvis, Sow., 

 Pecten eequivalvis, Sow. 



Ammonites maculatus, Cardium proximum, 

 Hunt. 



Avicula cygnipes, Phil., Cardium trunca- 

 tum,Fhi\.,Rhgnchonella tetrahedra, Sow., 

 R. acuta, Sow. 



