EXPLANATION OF THE PLATES. 



PLATE 11. 



This plate represents a fragment of the rock of Kinnoul, including the junction 

 of the schist and the trap. The vesicular cavities are seen running in lines 

 parallel to the laminae of the schist, and increasing in size and number 

 vk^here they approach to the trap. The contortion of the laminaj is also 

 represented at the points where the two rocks unite, and in the same place 

 the appearance of a detached fragment is visible. There is unquestionable 

 proof of the existence of such detached fragments in many cases, as they 



/ may be found entirely surrounded by the trap, and only discoverable after 

 breaking it. The conversion and prolongation of the schist into ramifying 

 veins is also shown, the schistose structure disappearing shortly after the 

 change takes place. 



PLATE 12. 



Forms of crystals to illustrate Mr. Phillips's paper on the Measurement of 

 Primitive Crystals by the reflecting goniometer. 



PLATE 13. 



Map and Sections of the Plastic Clay District on the south-east of London. 



The colours represent, 1. Chalk. 2. The formation of Plastic clay. 3. That of 

 the London clay. 4. The tract of Marslies lying along the banks of the 

 Thames — the flat grounds of Southwark, St. George's fields, Battersea and 

 Chelsea, are coloured as belonging to this district, since they appear to 

 have remained in the state of unreclaimed marnhes even within the period 

 of historical record : beneath a great part of this district lie the remains of 

 an extensive forest, (vide page S04). 



The numbers marked tipon the map denote various points, where either natural 

 sections are exhibited or where pits have been opened. 



1. Marks the section ascertained by Sir Christopher Wren while laying the 

 foundations of the new Cathedral of St. Paul ; see Parentalia and page 287 

 of this volume. 



2. The Tcinnel at Rotherhithe or Redriffe ; see the section as given in Mr. 

 Webster's paper on the Strata lying over the Chalk, Geol. Trans, vol. ii. 

 page 197. It should be observed that the section of the sunt sf^rn shaft only 

 is there given. In the northern a thickness of nearly forty feet of the 

 London clay was exhibited, in consequence of the dip of the strata in that 

 direction. 



3. Between Camberwell and Peckham. Here the shelly beds of the Plastic 

 clay have been found in digging wells at the depth of thirty feet. At New 

 Cross, near this point, they are found at the surface. 



