78 



MIDDLE LIAS. 



LiTHOLOGY. Thickness. Organic Remains. 



Elevation, feet. 

 No. 



13. The " Starfish Bed," hard, gray, mica- Ophioderma Egertoni, Brod., Ammonites Jim- 



ceous sandstone, large blocks from briatus. Sow., A. margaritatus, Mont., 



this bed lie on the shore 6 Belemnites elongatus. Mill. 



Zone of Ammonites capricornus. 



14. Gray marls, breaking up into cuboidal Ammonites capricornus, ^c\\\oi\\., A. Henleyi, 



masses ; in the upper part are several Sow., A. Bechei, Sow., A. Davcei, Sow. 



rows of small, fossiliferous nodules ; 

 this bed is much thicker, and better 



seen at Golden Cap "6 



Base of Down Cliffs 



The gray or micaceous marls attain a great thickness at Golden Cap, where they rest 

 on the Belemnite bed. These marls contain several stages of life, which have not been 

 worked out with sufficient accuracy, to enable me to define the limits of the different zones. 

 Fragments of Ammotiites Jamesoni have been collected in the lower part of this deposit, and 

 Ammonites Davai, capricornus, and Bechei, in the upper. In Gloucestershire beneath 

 the zone of Ammonites capricornus two other zones are found characterised by Ammonites 

 Ibex and Ammonites Jamesoni, and these are likewise doubtless comprised in the gray, 

 micaceous marls at Golden Cap, which here attain so great a thickness. 



7. The Zone of Ammonites Jamesoni. 



Synonyms. — " Micaceous marl, in part," De la Beche's section. " Numismalismergel 

 oder Belemnitenmergel," Quenstedt, ' das Flotzgebirge Wiirtemberg." " Lias Gamma, 

 pars," Quenst., ' der Jura Uebersichtstafel,' p. 293. "Die Schichten Ae^ Ammonites Jamesoni," 

 Oppel, 'die Juraformation/ p. 118. " Jamesoni-bed," Wright, ' Quart. Jour. Geol. Soc.,' 

 vol. xiv, p. 25. 



In Gloucestershire the beds representing this zone are found only in some deep brick- 

 pits near Leckhampton, in the environs of Cheltenham, from whence I obtained frag- 

 ments of a large Ammonites Jamesoni, Sow., and many of the young forms of this species 

 known as A. Bronni, Rom., with Rhynchonella rimosa, von Buch. 



The same Ammonites are found at Robin Hood's Bay, on the coast of Yorkshire, where 

 these beds at the west of the bay, according to Dr. Oppel, attain a thickness of 100 

 feet ; with Ammonites Jamesoni were associated Ammonites Taylori, Sow., Bel. elongatus, 

 Mill., Gryphcea ohliquata. Sow., Pholadomya decor ata, Ag., and Pinna folium, Phil. 



This zone is well developed in the Island of Pabba, near Skye, in the Hebrides, where 

 Ammonites Jamesoni is moderately abundant, if I may form an opinion from the number of 



