XXXI. Extracts from the Minute Book of the Geological Society, 



1810, February 2. 



AN Extract of a letter from Dr. Macdonell, of Belfast, to Mr. 

 Horner, was read, in which an account is given of a stratum of sub- 

 marine peat and timber in Belfast Lough, situated under the level 

 of ordinary tides, but generally left bare at ebb tides. Nuts are 

 numerous in it, both on the east and west sides of the harbour. 

 On the east side, where calcareous rocks exist, the nuts are filled 

 with calcareous spar, but on the west side, where the rocks are 

 schistose, they are empty. Some of them are perfectly filled, 

 others only partially so, yet the shell appears quite entire, and un- 

 changed by any petrifactive process, although when put into acids 

 some effervescence takes place. Dr. Hulton alledges that no infil- 

 tration can happen in circumstances similar to that in which these 

 nuts are placed, for they are immersed in a bed of peat four or five 

 feet thick, and this covered by a deposit of sand, shells, and blue 

 clay, and the whole kept moist and all evaporation prevented by 

 being covered three-fourths of the day by the tide. 



1811, January 18. 



An extract of a letter from Dr. MacDonnell, of Belfast, to Mr. 

 Horner, was read, giving an account of some granite veins in slate, 

 in the Mourne mountains. 



In some part of these mountains, which are situated at the south- 

 ern extremity of the county of Down, grey granite forms the sum- 



