Notes regarding the Serpentine Rocks on Dee Side. 315 



profusion of Silena inflata, then in full flower, but no where else 

 to be seen, and Arabis hispida. The rock is bare in many 

 places near the summits, of a greenish-grey colour, and much 

 softened and weather worn on the surface ; fissured like basalt, 

 but not regularly. The principal fissures, however, directed 

 pretty uniformly from SW. to NE. The summits seen from 

 NE. are conical and precipitous in some places, seen from N W. ; 

 they are more elongated but precipitous at their E. and W. ter- 

 minations. There are four or five of them. They rise a hun- 

 dred feet or two above the general mass of the mountain with- 

 in the space of about a square mile. The peculiar rock is, how- 

 ever, not confined to the summits, being seen at one place about 

 two miles N. of these near the level of the river. I could not 

 discover its junction with the granite. Many boulders of this 

 remarkable rock are scattered over the granite hills towards the 

 SE. even on the face of the steep hills beyond the river Muick, 

 which bounds the mass in question on the SE. flowing NE. in- 

 to the Dee. Many fragments of it are also found in the bed of 

 the Dee below the junction of the Muick; but although I 

 passed frequently over the ground, I could find no boulders to 

 the N. or N W. There is asbestus in the bed of the Muick near 

 the base of the Coil. But the specimen herewith sent is very 

 remarkable for the quantity of fixed magnetism which it pos- 

 sesses. The poles are in the line of the stroke of the hammer 

 which broke it ofi", the place that received the stroke attracting 

 strongly the south pole of a magnet, and the opposite end of 

 the specimen the north pole. The stroke was at the point, 

 where the weather-worn surface is yet seen. 

 Alfoud, December 19. 1829. 



On the Hya-hya or Milk-Tree of Demerara. In a Letter to 

 Professor Jameson from James Smith, Esq.* 



^Whoever has read Humboldt's Travels to the Equinoctial 

 Regions of this Continent, cannot but have felt his imagination 



• The important discovery contained in this communication from my for- 

 mer pupil, Mr Smith, cannot fail to interest our readers. Ere long we shall 

 be able to publish in the Journal further particulars in regard to the milk' 

 tree, and other remarkable trees of Demerara. 



