Chap. X.] valuda\uii and arrialoor groups — pondiciierry. 153 



characteristic ' Arrlaloor' species, are also very abundant, and Nerita 

 degans, a Trigonia, ( T. semiculta ?) and several other species, many of 

 them yet undescribed, occur in smaller numbers. This bed may be 

 clearly traced for a distance of about half a mile, striking S. S. W., 

 and where it crosses the canal just above the sluice gates, it is seen in 

 section dipping about 2° or 3° to the South-east. At this point it is a 

 concretionary limestone, having lost much of its conglomeratic charactei* 

 and containing few fossils, and those not in a recognizable condition. 

 In one respect it is peculiarj being full of contorted cylindrical casts, 

 about half an inch in thickness, which appear to pierce the stone in 

 every direction, although they only become visible when weathered^ 

 The origin of them it is difficult to explain satisfactorily ; the most pro- 

 bable supposition is that they are casts of the borings of annelids in 

 hard sand, such as may well have been the original material of the 

 bed. This bed, preserving the same mineral character, may be traced 

 for nearly a mile along the canal, being visible just above the water, 

 when the latter is low, and further indicated by a great quantity of 

 stony debris scattered along the right bank. It then turns abruptly 

 to the Westward, and is lost in the soil in the neighbourhood of 

 Ossatary tank. 



Returning to the starting point near Valudayur, and proceedlno- 

 thence in an opposite direction, we soon lose the out-crop of the 

 bed beneath the cotton soil with which the ground is uniformly' 

 covered. The little bank formed by the hard projecting edges of 

 tlie bed becomes merged in a gentle grassy slope facing to the Norths 

 which trends away in the direction of Sydrapet (Sudarampet), and for 

 about a mile little is to be seen but loose fragments of conglomerate 

 scattered over the surface, and a few larger blocks half buried 

 in the soil. Imbedded in, and intermingled with these, I have 

 obtained Ostrea tegulanea, Fungia Jilamentosa, and other common 

 " Arrialoor " species, also Nautilus Danicus and N. BouchardianuS) 



