382 Astronomical Society. 



It appeared to Mr. Gordon impossible that these roots 

 could have supported different trees all growing at the same , 

 time ; for the distinct ramifications of these (horizontally like 

 Scotch firs at the present day) are bedded in moss perpendi- 

 cular above each other. 



April 23.— A paper was read entitled " Some Observations 

 on the Lakes of Canada, their Shores, Communications," &c. 

 by Lieut. Portlock, R.E. 



In this memoir the author describes the various nature of 

 the shores of Lakes Huron, Michigan, Erie, and the other 

 lakes of Canada, and annexes a plan, in which a tabular view 

 is presented of the comparative level of these lakes and their 

 communications with each other. At the Falls of Niagara, he 

 observes that the upper stratum is a firm compact limestone rest- 

 ing on strata of a very schistose nature. It is not by erosion of 

 the surface that the falls are made to recede ; but the waters, 

 after falling 150 feet, strike the bottom, and are reduced to 

 foam ; they are then driven up into the air far above the rock 

 whence they had descended : this penetrating foam acts on 

 the lower argillaceous strata, till the overhanging rock is un- 

 dermined. Lieut. Portlock remarks, that there has been a 

 gradual fall in the level of the Lakes at Canada. He also 

 offers some considerations on the proximity of the sources of 

 several rivers which flow in opposite directions. 



May 7. — A paper " On the Geology of the Ponza Islands, 

 in the Mediterranean," by G. P. Scrope, Esq. M.G.S., was 

 read in part. 



A letter was read from Thomas Botfield, Esq., M.G.S., 

 accompanied by a collection of bones and horns of the deer, 

 and bones of man and other animals, found in a cleft of the 

 rock at a quarry at Hincks' bay, (near the Old Park iron 

 works,) in the parish of Dawley and county of Salop. Their 

 adhesion when applied to the tongue showed that the animal 

 gelatine was nearly gone, which does not take place till after a 

 long period of inhumation. 



ASTRONOMICAL SOCIETY. 



May 14. — The whole of this sitting of the Society was 

 occupied by the reading of the conclusion of Mr. Baily's 

 paper On the Method of determining the Difference of Me- 

 ridians, by the Culmination of the Moon, this paper having 

 been commenced at the last meeting in April. 



The author, after briefly alluding to the nautical methods of 

 determining the longitude, including those by means of chro- 

 nometers, adverted to five distinct astronomical methods 

 which have been pursued, viz. 1st, By the eclipses of Jupi- 

 ter's satellites. 2dly, By eclipses of the moon. 3dly, By 



eclipses 



