﻿Geological Society. 71 



of p and P ; and then equations (1) and (2) can be separately- 

 solved without elimination, giving respectively Y and P . 



Second Form. — Each of the component streams flows through a 

 passage whose factor of resistance, f, is given, from a separate reser- 

 voir in which the pressure p and the elevation z of the surface above 

 the junction-chamber are given. The resultant stream flows through 

 a passage whose factor of resistance, F, is given, into a reservoir in 

 which the pressure P and the elevation Z of the surface above the 

 junction-chamber are given. These, together with the areas A, a l9 

 a 2 , &c, are the quantities given. The functional values given are 

 those of the bulkiness, * 0>1 , s 0>2 , &c. and S , as before; also the fol- 

 lowing values of the velocities, according to well-known principles in 

 hydrodynamics. For any component stream, 



*+ 2 f sd P \ 



JPo h r . ... .. (O) 



•V| 



and for the resultant stream, 



VJ 2 HI 



( 1+F 



SdP 



h ( 6 ) 



The functional values given are to be substituted in equations (1) 

 and (2), whose solution will then give the numerical values of^? and 

 P n ; and from these and the other data the numerical values of v. 



&c. and of Y may be calculated. 



GEOLOGICAL SOCIETY. 



[Continued from vol. xl. p. 388.] 



June 8th, 1870. — Joseph Prestwich, Esq., F.K.S., President, 

 in the Chair. 



The following communications were read : — 



1. "On the Superficial Deposits of the South of Hampshire and 

 the Isle of Wight." By Thomas Codrington, Esq., F.G.S. 



This paper treated of the gravel deposits covering the tertiary 

 strata of the country between Portsmouth and Poole, and of the 

 Isle of "Wight. 



The strikingly tabular character of the surface is best seen on the 

 east of the Avon, where from the coast for more than twenty miles 

 inland a gravel-covered plain can be followed, rising gradually from 

 80 feet to 420 feet above the sea, at the rate of about 20 feet per 

 mile. The high plains of the New Forest, to the eye perfectly level, 

 and indented by deep valleys, are portions of this table-land. The 

 plateau between the Bournemouth Cliffs and the Yalley of the Stour, 

 and detached gravel-capped hills further inland, are the remnants of 

 a similar table-land on the west of the Avon, while eastwards the 

 same character prevails up to Southampton "Water. Sections parallel 

 with the coast show the level nature of the country, broken only by 

 well-defined river-valleys. On the east of Southampton Water a 



