6i 



the truth of the general belief that the very mild climate of 

 these islands is mainly due to the drift of comparatively warm 

 water which washes their shores. 



On the same evening, 



Dr. James Thomson, C.E., read a paper on " Shrinking 

 and Warping of Woods in Drying," of which no abstract has 

 been furnished to the Secretaries. 



On Wednesday evening, April 5th, Mr. William Gray 

 delivered a lecture on "The Ammonite: its Ancient and 

 Modern Relatives." After giving a general description of the 

 geology of the north-east of Ireland, he referred to the white 

 limestone or Chalk, and the Blue Lias below the Chalk as the 

 representatives of two of the great groups into which geolo- 

 gists divide the rocks which compose the earth's crust. The 

 Chalk being the most recent, and the Lias the oldest, 

 they embrace elsewhere a series of rocks several thousand 

 feet thick, and denote a period of geological time when a 

 peculiar kind of shellfish lived, called the Ammonite, a crea- 

 ture that became extinct before our limestone cliffs were 

 elevated from the sea bottom, where the Chalk was first de- 

 posited as mud, like that now forming in the Atlantic. They, 

 however, lived for ages previously, and even on the shores of 

 the old sea in which our limestone was formed, the then 

 living Ammonites might have been found with the long- 

 fossilised remains of the generations of Ammonites that 

 crowded the ancient sea in which the Lias rocks were formed, 

 just as we now collect the Chalk and Lias Ammonites on the 

 shore of Lame Lough, mixed up with the living shells of the 

 adjoining sea. From the first appearance of this genus in 



