162 G. W. and F. M. Balfour — On the East Lothian Coast. 



Fig. 1. — Map of Strata at "WTiitberry Point. Scale, 6 in, to the mile. 



A. Lava slieet. 



B. Sandstone Beds, dipping from every side towards the Lava. 

 CC. Line of Section along which Fig. 2 is supposed to be drawn. 



We conceive that the phenomenon is to be explained by supposing 

 the orifice through which the lava rose and overflowed the surface 

 of the sedimentary strata to have been very much smaller in area 

 than the extent of igneous rock at present visible ; and that the 

 pressure of the erupted mass on the soft beds beneath, aided perhaps 

 by the abstraction of matter from below, caused them to incline towards 

 the central point at a gradually increasing angle. The Diagram, Fig. 2, 

 Fi(j. 2.— Vertical Section through CC. Diagram (Fig. 1). 





A. Orifice by which the lava ascended. 



B. Sandstone Beds. 



B'. Hypothetical extension of ditto. 



C. Sheet of lava spread over the sandstones B. 

 C. Hypothetical extension of ditto. 



will serve further to illustrate this hypothesis. A. is the neck or 

 orifice by which the melted matter is supposed to ascend. C. shows 



