VINE : CAMBKIDGE GREENS AND. 
29 
Description of Plate II. 
Fig. 7. Stomatopora gracilis, Milne Edwards (?) x 33 dia. 
^ Fi^. 8. Diastopora cretacea, Vine. Var. Lineata, Vine, x 33 
dia. 
Fig. 9. „ megalopora, Vine. 9a, and db, Ovicells of 
anotiier specimen, 9c, Natural size of Colony. 
Fig, 10. Membranipora Dumerilli, Var. cantabrigensis. Vine. 
a few cells showing the ovicell and 
avicularia. 
Fig. 11. Microporella (? antiquata). The most characteristic 
cells of the species described. 
FORAMINIFEEA. 
Fig. 12, Trochammini helveto-jurassica, Hausler. 
Fig. 12a, Portion of the wall of Chamber, x 130 times. 
Fig. 13, Webbina Isevis, Sollas. 
Fig. 14, „ tuberculata. Sollas. 
Fig. 15, Variety (?) of 2\ helveto-jurassica. 
Fig. 16, „ (?) „ „ „ (Haplophragmium ? 
Reuss.) 
Fig. 17, Textularia agglutinans (?) D'Orb. 
The whole of the above, except 12a, reduced from large 
Camera drawings. 
ON THE ORIGIN OF THE CHALK DALES OF YORKSHIRE. BY 
J. R. MORTIMER, P.G.S. 
The great interest attaching to the formatiqp of the Chalk 
Valleys has been much increased by an able Paper read by the 
Rev. E. M. Cole, of Wetwang, at a meeting of the Members of the 
Yorkshire Geological and Polytechnic Society, held at Driffield, 
July 2nd, 1879.* 
Mr. Cole if I understand him rightly, attributed the formation 
of those dales to erosion subaerial, submarine and glacial. In 
the subsequent discussion, Mr. Dakyns of the Geological Survey, 
* York. Geol. and Polyt. Society, VoL VII., Part II., p. 128. 
