EXPLANATION OF THE PLATES. 5 



27. Sundridge Park. Here are the remarkable pits of indurated shelly a^ravel, 

 described by Mr. Parkinson, Geol. Trans, vol. i. and p. 299 of this paper. 



28. Between Sundridge Park and Camden PJace, in the bottom of the valley, is 

 a chalk pit covered with inferior sand of the plastic claj formation. 



SECTIONS. 



All these sections have been constructed on double scales, viz. a larger scale for 

 the heights or vertical distances and a smaller for tlse horizontal distances. 



No. 1. General Section from Redriffe Tunnel to Knockholt beeches. 



This is carried along the line of section marked in the map. The scale for hori- 

 zontal distance is nearly tlie same as in the map. The colours also are the 

 same, wi(h the exception that the thick stratum of white sand which forms 

 the lowest member of tlie plastic clay formation, is here distinguished from 

 the other members of that formation by dotting it. 



No. 2. Section of the pits upon Loam Pit Hill, see page 285. The strata are 

 here coloured after nature ; their resemblance to those of Alum bay in the 

 Isle of Wigiit will instantly strike the eye on comparing this section with 

 that accompanying Mr. Webster's paper, Geol. Trans, vol. ii. 



No. 3. Section of the Great Sand Pits at Woolwich; described page 284. This 

 section agrees with the preceding in its scale, in its colouring, and generally 

 in the strata which it exhibits; but the partial changes which occur in 

 diflferent points of tlie same deposits will be likewise observed in comparing 

 them together : the direct distance of these pits from those of Loam Pit 

 Hill is rather more than three miles. 



PLATES 14, 15, ]6, 17, 18, ID, '^0, 21, 22. 



Views, Maps, and Sections to illustrate Dr. Mac Culloch's paper on the Parallel 



Roads of Glen Roy. 

 Plate 14. A view in the upper part of Glen Roy, representing the terraces and 



the character of the valley at its commencement. The slope on the right of 



the picture is part of one of these terraces. 

 Plate 15. A view lower down, representing the coincidence between the terraces 



and one of the lines. The entrance of Glen Turit is seen in the distance. 

 Plate 16. A view from near Glen Fintec, comprising that part of the valley 



where the most perfect and uninterrupted continuity of the several li/ics is 



visible. On the hill which forms the distances of the picture they are also 



most perfect in their dimensions and forms. 

 Plate 17. A view lower down the valley. It serves to represent among other 



things the disappearance of a line wheie no assignable reason for its absence 



exists. 



