Abou-zeyd describes them as, "Un animal de mer qui resemble a l'ecrevisse; quand cet animal sort de la mer, _il se convertit en pierre_." See REINAUD, _Voyages faits par les Arabes_, vol.
i.p.21.The Arabs then; and the Chinese at the present day, use these petrifactions when powdered as a specific for diseases of the eye.] _Mountain System_ .-- At whatever period the mountains of Ceylon may have been raised, the centre of maximum energy must have been in the vicinity of Adam's Peak, the group immediately surrounding which has thus acquired an elevation of from six to eight thousand feet above the sea.[1] The uplifting force seems to have been exerted from south-west to north-east; and although there is much confusion in many of the intersecting ridges, the lower ranges, especially those to the south and west of Adam's Peak, from Saffragam to Ambogammoa, manifest a remarkable tendency to run in parallel ridges in a direction from south-east to north-west.
[Footnote 1: The following are the heights of a few of the most remarkable places:-- Pedrotallagalla 8280 English feet.
Kirrigalpotta 7810 English feet.
Totapella 7720 English feet.
Adam's Peak 7420 English feet.
Nammoone-Koolle 6740 English feet.
Plain of Neuera-ellia 6210 English feet.] Towards the north, on the contrary, the offsets of the mountain system, with the exception of those which stretch towards Trincomalie, radiate to short distances in various directions, and speedily sink down to the level of the plain.

Detached hills of great altitude are rare, the most celebrated being that of Mihintala, which overlooks the sacred city of Anarajapoora: and Sigiri is the only example in Ceylon of those solitary acclivities, which form so remarkable a feature in the table-land of the Dekkan, starting abruptly from the plain with scarped and perpendicular sides, and converted by the Indians into strongholds, accessible only by precipitous pathways, or steps hewn in the solid rock.
The crest of the Ceylon mountains is of stratified crystalline rock, especially gneiss, with extensive veins of quartz, and through this the granite has been everywhere intruded, distorting the riven strata, and tilting them at all angles to the horizon.

Hence at the abrupt terminations of some of the chains in the district of Saffragam, plutonic rocks are seen mingled with the dislocated gneiss.

Basalt makes its appearance both at Galle and Trincomalie.

In one place to the east of Pettigalle-Kanda, the rocks have been broken up in such confusion as to resemble the effect of volcanic action--huge masses overhang each other like suddenly-cooled lava; and Dr.Gygax, a Swiss mineralogist, who was employed by the Government in 1847 to examine and report on the mineral resources of the district, stated, on his return, that having seen the volcanoes of the Azores, he found a "strange similarity at this spot to one of the semi-craters round the trachytic ridge of Seticidadas, in the island of St.Michael."[1] [Footnote 1: Beyond the very slightest symptoms of disturbance, earthquakes are unknown in Ceylon: and although its geology exhibits little evidence of volcanic action (with the exception of the basalt, which occasionally presents an appearance approaching to that of lava), there are some other incidents that seem to suggest the vicinity of fire; more particularly the occurrence of springs of high temperature, one at Badulla, one at Kitool, near Bintenne, another near Yavi Ooto, in the Veddah country, and a fourth at Cannea, near Trincomalie.