244 MR. A. W. WATERS ON FOSSIL LITHOTHAMNIA. 



having had a pressure below the average ; and August was 

 only a few thousandths of an inch above the average : — 



Difference from mean. 



1872. in. 



January — 0*315 



February —0*205 



March —0*139 



April —0*032 



May — 0*050 



June —0*107 



July —0*017 



August 4-o*oo6 



September — 0*161 



October —0*195 



November —0*291 



December —0*367 



Comparison of these departures below the average with 

 the separate monthly values of the rainfall for 1872 does 

 not show that the greatest rainfall occurred in those months 

 in which the pressure was the most below the average ; 

 but the almost constant depression throughout the year 

 certainly does so : it is probable that, if a longer and more 

 complete register could be examined, 1872 had a lower 

 mean pressure than any year over a very long period, just 

 as it had a greater rainfall than any year for a very long 

 period, say eighty years. 



XXXI. Notes on fossil Lithothamnia [so-called Nullipara) 

 By Arthur William Waters, F.G.S. 



Read January 27th, 1874. 



The organisms on the table before us have been assigned 

 very various places in the organic or inorganic kingdoms 



