440 Capt. Cullen's Notice of the Geological Features 



pearance of greater dimension. Its extreme narrowness, deep 

 black colour, and the total absence of all traces of vegetation, 

 formed a singular contrast to the rest of the hills, which were 

 covered with long dry grass, and scattered jungle bushes. The 

 connection of this singular bed of trap with the rocks at its 

 two extremities, would probably offer a most instructive sub- 

 ject of investigation. 



At the end, near Banaganapilly, it first offers itself to no- 

 tice in a small, steep, conical hill, composed solely of green- 

 stone. I had previously, however, immediately almost on 

 leaving Banaganapilly, observed several partial appearances 

 of lines of black rock, jutting out a few feet above the soil, in 

 the plain on the north side of and near the base of the Bana- 

 ganapilly promontory. These, I have now little doubt, were 

 a continuation of the green-stone bed. But it is at the western 

 extremity at the head of the valley, close to Jeldroogum, where 

 the hills close in on all sides, and where the route is crossed 

 by the bed of trap, and all the rocks with which it is asso- 

 ciated, that the attention is most forcibly excited. About one- 

 half or one-third of a mile west of Jeldroogum the route lies 

 over a ghaut, or ridge, of 300 or 350 feet perpendicular height, 

 and, descending nearly as much on the opposite side, continues 

 up a pretty level narrow valley for a mile or two, and then 

 finally leads up another ghaut, of about the same height, on 

 to a continuous table land, extending to Piaplee. 



Blocks of limestone, of a light blue or gray colour, are com- 

 mon in the interval between Jeldroogum and the ghaut; but 

 the low hills, forming the foot of the ghaut, were covered with 

 large dark masses of rock, which I had imagined to be trap, 

 but which, on examination, also proved to be limestone of a 

 very dark blue. Limestones of other colours were also found 

 intermixed, such as green, gray, &c. ; the former on fracture, 

 at a little distance, resembling a good deal a fine-grained green- 

 stone ; but the whole of these were covered with a dark crust 

 of clay-slate, so that, unless close to them, it was not easy to 

 distinguish the line of separation between the limestone and 

 trap, which was the next in the order of succession, and at 

 only a short distance from the foot. 



The trap was again succeeded by limestone, and the latter 

 by clay-slate, nearly to the summit, which was capped with 

 rock of a beautiful flesh colour, with specks and shades of a 

 delicate green, as if connected with its vicinity to the trap, and 

 of so close and fine a texture as to appear homogeneous even 

 through a lens. It exhibited a conchoidal fracture. The de- 

 scent of the ghaut on the opposite side consisted of clay-slate 

 nearly to the foot, when the limestone reappeared, and these 



two 



