G. W. Lamplugh — The Boulder-clay at Bridlington. 393 



EXPLANATION OF PLATE X. 



(Figs. 1-3, Carboniferous, Highlands, Sumatra.) 



Fig. 1. Spirifera glabra, Martin, sp. (ventral valve). 



,, 2. Productus undatus, Defrance (ventral valve). 



„ 3. semireticulatus, Martin (ventral valve). 



„ 4. Sparganilithes gemmatus, H. Woodw., fruit of a Push-like plant, 



Tertiary Coal-shales, Sumatra. 



,, 5. Cardita Sumatrensis, H. Woodw., Tertiary, Sumatra. 



„ 6. Cardita, sp. (cast of) „ „ 



,, 7. Lucina, sp. (cast of) ,, „ 



,, 8. Dosinia cretacea, Reeve, Miocene Tertiary ? Island of Nias. 



„ 9. Area Verbeekii, H. Woodw., „ ,, 



,, 10. Meiocardia sub-Cumingii ,, „ 



„ 11. Hemicardium, Island of Nias. 



„ 12. Pecten, sp. „ 



„ 13. „ sp. „ 



„ 14. Callista, sp. (cast) ,, 



,, 15. Cytherea (cast) „ 



,, 16. Lunulicardium limaforme, H. "Woodw., Island of Nias. 



„ 17. Spine of Cidaris ; Padang Highlands, West Coast of Sumatra. 



(To be continued in our next Number.') 



II. — On the Occurrence of Freshwater Eemains in the 



Boulder-clay at Bridlington. 



By G. W. Lamplugh, Esq. 



j^N this part of the Yorkshire coast, the storms of last winter have 

 often bared parts of the beach, for a time, of tbeir usual covering 

 of sand and shingle, and have thus exposed to observation many 

 interesting features in connexion with the Drift series. Of these, 

 the most instructive point which has come under my notice is the 

 one which forms the immediate subject of the present communication. 



In an exposure, on the beach, to the north of Bridlington, I saw 

 freshwater remains, intermingled with and covered by a Boulder- 

 clay. But before proceeding to details, it will perhaps be better to 

 give a brief account of the chief divisions of the glacial beds in the 

 neighbourhood, without a knowledge of which, the reader might 

 find much difficulty in understanding the continual references made, 

 in the sequel, to these divisions. 



The base of the series is generally believed to be formed by the 

 "Basement" clay, which Mr. S. V. Wood has shown 1 to be the 

 same as the " Great Chalky Boulder-clay " of the country further 

 south. I pointed out in a former paper, 3 that this clay extended as far 

 north as Bridlington, and there contained the bed of sand with Arctic 

 shells long known as the " Bridlington Crag." Still more recently 

 I have seen the same clay in a very interesting exposure in Filey 

 Bay (north of Flambro' Head), opposite the village of Keighton, 

 and here also it contained streaks of a clean blue clay, with many 

 crushed shells, identical in all respects with similar streaks in the 

 same clay at Bridlington, which are considered as forming part of 

 the " Bridlington Crag." 



1 Quart. Journ. Geol. Soc. vol. xxiv. p. 146. 



2 Geol. Mag. 1878, p. 509; see also Note, p. 573. 



