ZONE OF AEGOCERAS HENLEYI. 



89 



ECHINODERMATA. 



Cidaris Edwardsii, Wright. 

 Rabdocidaris Moraldina, Colt. 

 Hemipedina Jardinii, Wright. 

 Uraster Gaveyi, Forb. 

 Tropidaster pecdnatus, Forb. 



Ophioderma Gaveyi, Wrt. 



— Brodiei, Wrt. 

 Pentacrinus robustus, Wrt. 



— punctiferus, Querist. 



— subangularis, Mill. 



In Dorsetshire this zone occupies a conspicuous position in the cliff sections, as at 

 Black Ven, Stonebarrow Hill, Westhay Cliff, and at the Goklen Cap, all of which 

 exhibit profiles of the beds. Mr. E. C. H. Day, E.G.S.,^ has given an exhaustive 

 description of these in his excellent memoir ; and, as I had the pleasure of working over 

 some of the sections with my friend, I select that at the Golden Cap as the most typical 

 for a general view of the whole. The lower portion of this headland consists of — 



I. The Upper Marls, without mica, of De la Beche's section, in which a greater 

 number of Belemnites are found than in any other division of the Lias ; seams of grey 

 marls full of these fossils are seen along the shore at low tide. Belemnites longisshnus. 

 Mill., B. elo7rgatus. Mill., and B. clavaius, Scliloth., appear to be the prevailing forms. 

 Here, likewise, are found Lytoceras fmbriatum, Aeg. Bechei, Aeg. Henley i, Aeg. 

 striatum, Phglloceras Loscomhi, Nautilus semistriatus, d'Orb., Nautilus inornatus, Trochus 

 imbricatus, Eucyclus Gaudryanus, Chemnitzia Periniana, Pleurotomaria similis, Cryptcenia 

 expansa, Inoceramus ventricosus, Hinnites tumidus, Plieatula spinosa, Pecten sp. 



H. The next strata in ascending order are known to local collectors as the " Green 

 Ammonite-beds,'' as they afford a rich harvest of fossils, which are well preserved in the 

 greenish non-micaceous marls that constitute this stage. It was in these I found 

 the specimens of Aegoceras Henleyi, which have enabled me to demonstrate the remarkable 

 history of this species, so long misunderstood by palaeontologists, and Aegoceras Lavcei, 

 the rarest Cephalopod in the locality, associated with Aeg. Bechei and Monotia 

 inaquivalvis in the same small slab. 



Fossils of the Green Ammonite-beds, near Char mouth. 



Ichthyosaurus. 

 Plesiosaurus. 

 Aegoceras Henleyi, Sow. 



— Bechei, Sow. 



— striatum, Reiiiecke. 



— Davoei, Sow. 

 Lylocera.s fimbriatum, Sow. 

 Phylloceras Loscombi, Sow. 



Nautilus semistriatus, d'Orb. 

 Belemnites longissimue, Mill. 

 — compressus, Stahl. 

 Cryptgenia expansa, Sow. 

 Chemnitzia Carncensis, d'Orb. 

 Pterocera liasina, d'Orb. 

 Inoceramus ventricosus. Sow, 

 Monotis insequivalvis, Sow. 



^ "The Middle and Upper Lias of the Dorsetshire Coast," 'Quart. Journ. Geol. Soc.,' vol. .xix, 

 p. 278, 1863. 



2 Ibid., p. 283. 



12 



