382 



EEV. A. IEYIXG- 0~N THE PHYSICAL HISTOEY OE 



Portree, I find pretty nearly the same genera occurring in a very" 

 similar state.] 



Steatigeaphical Evidence. 



Data for Section A (fig. 1). — The well-section at Wellington 

 College (see Quart. Journ. Geol. Soc. vol. xli. p. 494) is the standard 

 for comparison. The sequence of the beds at the southern end of the 

 section has been proved again in a new well, this winter, behind 

 the Wellington Hotel. The thickness of the sand beds below no. 10 

 is calculated (from the altitudes of the London Clay in the College 

 well-section and at its outcrop to the jST.W.) as 80 feet. The 

 green earthy sands (nos. 7, 8) are proved by outcrop and inter- 

 mediate excavations to continue to the brook parallel to the railway 

 3 mile to the E. 



Section B. Brook-section south of Ravensiuood. 



ft. 



a. Green earths and sands (nos. 7, 8) 20 to 25 



b. Clays, loams, ferruginous sands with strong clay-lavers 1 9 f| 



(nos. 9, 10) J" U 



On the west side of the line the well at the lodge by the Roman 

 Road pierced beds nos. 9, 10, 11. The last-mentioned bed is a dirty 

 quartz-sand, blackish green, with much lignite and pyrites. 



Section C. New Well by Wokingham- Sandhurst Road. 



ft. 



a. Angular and pebbly drift-gravel 6 



b. Brown and yellow ferruginous sand, loam and clay (partly laminated), 1 



with irony nodules, very clayey in upper part (nos. 9, 10) J * J 



c. Greenish-black quartz-sand with pyrites, lignite, and freshwater dia- "1 ~ 

 toms (pierced to) J 



Total depth 32 



On the assumption that things which are equivalent to the same 

 thing are equivalent to one another, I maintain that the beds of the 

 new well are precisely on the same horizons as those in the well at 

 the lodge (see fig. 1), since the upper bed in each of the wells is the 

 equivalent of the beds nos. 9 and 10 of the brook-section (B). 

 North of the new well the beds nos. 9 and 10 are cut through by 

 the brook ; but no. 9 is recognized at the top of the hill just N. of 

 Jack's Bridge (see Ordnance map) ; and the base of no. 10 is expose^ 

 some 20 ft. lower in the banks of King's Mere, the bottom of which 

 basin is in no. 11, a fine quartz sand *. J^os. 9 and 10 can be recog- 

 nized in the railway- cutting both BT. and S. of Nine-mile Hide. 

 There are two larger exposures of no. 10, — (a) in a sand-hole by the 

 roadside, (6) in the railway- cutting (see fig. 1) \ mile N". of the 

 road. Beneath no. 10 the fine quartz-sand of no. 11 is well exposed 



* The lake was dried up last summer. The above statement is from my own 

 observation ; the previous statement (vol. xli. p. 503) was made from information 

 given rae by others. 



