OBSERVATIONS. 
363 
tinual drifting of fine siliceous sand, or the action of the atmosphere 
under exposure to a burning sun. A similar gloss appears on the 
surface of many fragments of flint and compact siliceous limestone 
that have been long exposed on the surface of the soil, on the 
summit of Martre near Paris ; and in this case, I think, it can only 
be referred to the action of the sun and atmosphere. 
The chain of the Soudah or Black Mountains appears to be 
composed of this basalt; they rise to an elevation of about 1500 
feet, being situated at a short distance on the south from Sockna, 
and extending about 100 miles in breadth from north to south, and 
in length as far as the eye can reach, from east to west ; they are 
perfectly barren, of irregular form, occasionally broken into detached 
masses, and sometimes rising into cones. Their elevated plains are 
in some parts covered with the small spherical shining fragments 
above described. The latitude of this chain is from 28-40. to 27*30. 
north. Traces of basalt occur also near TripoU, in lat. 32. at a 
spot called Black Dog, on the north of Beneabbas, and in a valley 
through which the road passes from Beneabbas to Benioleed. 
2. An unrolled agate from Om el a Beed, near Zeghen, on the 
south of the Black Mountains. The occurrence of fragments of 
basalt, in this same neighbourhood, renders it probable that basaltic 
rocks exist in Situ, near the Pass of Kenair. 
' TERTIARY FORMATIONS. 
3. Two species of cardium, in a state of delicate preservation, 
resembling that of the shells of Grignon, near Paris, and embedded 
in a loose white sand, which has the appearance and degree of 
adhesion of coarse white sugar, from a gravelly plain on the north 
of Bonjem. 
4. Slightly crystalline limestone, of a dark yellow colour, and 
loaded with fragments of organic remains, amongst which the most 
distinct are referrible to the genus Ostrea and Pecton. It is found 
in a mountain of Tripoli, thirty miles south of Benioleed. This 
3 A 2 
4 
