TRANSACTIONS OF SECTION C. 765 



The deepest part of the wall trenches was about forty feet, but the general 

 depth was thirty to thirty-four feet below O.U. 



The trench of the eastern wall showed the following section at the south end. 



Ft. In. 



Laminated Warp 12 



Shell Bed 3 



Silt . . • 10 



Shell Bed 10 



Glacial Gravels 110 



Compact Boulder Clay 3 



Towards the north the surface of the Boulder Clay rises, a bed of stoneless red 

 clay intrudes in the upper portion of the gravels, a peat bed makes its appearance, 

 one of the shell beds disappears, and the toe of a sandy balk is introduced under 

 the warp. At the north end of this trench there are two beds of Boulder Clay 

 separated by gravels, the red clay having disappeared ; otherwise the section is 

 similar to that last described. 



The shell bed contained Cardium edule, Tellina solidula, Scrobicularia 

 piperata, Utriculus obtusus, E,issoa ulva, Littorina rudis, L. obtusata, Mytilus 

 edulis, Pholas Candida, and Nassa incrassata, the latter five being new records 

 for this bed. 



The large number of very young specimens and both valves being often intact 

 indicate but a short journey and beach-like conditions. 



The surffice of the clay and peat bed was level and undisturbed, except that 

 the smaller shells of the shell bed above penetrated into numerous crack-like 

 crevices, and seemed to indicate that the clay had been exposed and sun-dried before 

 the waters of the estuary formed their shell beach. 



The shell bed underlying the warp and the method of deposition of the warp 

 appear to suggest that, whether the clay below was deposited under conditions due 

 to subsidence, suddeu or rapid, or not, a gradual subsidence took place during 

 the deposition of the warp. 



In the clay and peat bed there were stamps of trees, including oak (Quercus 

 pedunculata), with the roots extending several feet into the glacial beds below ; 

 a number of perfect cherries (Prunus Padus) were found, the quantity and con- 

 dition of wliich may suggest that the trees were bearing fruit at the time of the 

 first inundation ; a few pieces of charcoal grouped together were also found in this 

 bed, but careful search revealed nothing that could be attributed to human agency. 



Note. — Upper Shell Bed and top of Clay and Peat Bed, about 13 ft. below 

 O.D. ; High Water ordinary Spring Tides, about 12 ft. above O.D. ; Low Water 

 ordinary Spring Tides, about 10 ft. below O.D. 



5, The Jurassic Flora of East Yorkshire. By A. C. Seward, F.R.S. 



The plant-beds exposed in the cliff sections of the Yorkshire coast have 

 afforded unusually rich data towards a restoration of the characteristics and com- 

 position of a certain faciesof Mesozoic vegetation. Rich collections of plants from 

 Gristhorpe Bay and other well-known localities are found in the British Museum, 

 also in the Museums of Scarborough, Whitby, Cambridge, Oxford, Manchester, 

 York, Newcastle, Leeds, and elsewhere. The Natural History Museum, Paris, 

 contains several important Yorkshire plants, some of which have been described 

 by Brongniart and Saporta. The following species have been recognised from the 

 East Yorkshire area; — 



Marchantites erectus (Leek., ex Bean, MS.); Equisetites columnari/!, Brongn. ; 

 Equisetites Beani (Bunb.) ; Lycopodites falcatus, L. & H. ; Cladophlebis denticu- 

 lata (Brongn.) ; C. haiburnensis (L. & H.) ; C. lobifolia (Phill.) ; Coniopteris arguta 

 (L. & H.) ; C. hymenophylloides (Brongn.) ; C. quinqueloba (Phill.) ; Dictxjophyl- 

 Imn ruqo&um, L. & H. ; Klukia exilis (Phill.) ; Laccopteris polypodioide:^ (Brongn.); 

 L. Woodwardi (Leek.) ; Matonidium Goepperti (Ett.) ; Pfiehypteris lanceolata, 

 Brongn. ; IRufordia Goepperti (Dunk.) ; Sagenopteris Philliiisi (Brongn.) ; tSp/je- 



