34 REV. T. MACKERETH ON THE MEAN TEMPERATURES 



sometimes^ as in fig. 5^ filled in with carbonate of lime. I 

 have noticed that when carbonate of lime is deposited 

 in the cavity where the rod lay it is highly crystalline, and 

 could never be mistaken for any thing organic. Pig. 6 is 

 from a photograph showing the carbonate of lime in the 

 silica-centre. 



As the above remarks border on a subject which has 

 been discussed very extensively, I may be allowed to point 

 out that they settle one half of the discussion^ namely that 

 silica may be dissolved in presence of calcareous fossils ; 

 but the other half, namely whether or not the spaces so 

 left may be filled up with carbonate of lime so as to look 

 like fossils, is still an open question. 



V. On the Mean Temperatures of the Winters of the last 

 Twenty-nine Years. By the Rev. Thomas Macke- 

 RETH, r.E.A.S. &c. 



Head before the Physical and Mathematical Section, 

 February 25th, 1879. 



It may be considered somewhat premature to institute a 

 comparison of the mean temperatures of the last twenty- 

 nine years when the colder of the extremes of the winter 

 months has not yet been entered upon, viz. the month of 

 March. In a meteorological sense Avinter may be consi- 

 dered as including five months of the year, viz. November, 

 December, January, February, and March. But January, 



