Chap, IX.] arrialoor group — verdachei.lum area. 147 



nullabs. A fevv traces of it are seen near where it crosses the Verdachel- 

 lum and Oolunderpet road, at Pulliput, but all the country to the North, 

 as far as Ohendamungalum, is so deeply covered with soil, that nothing is 

 seen except in wells, and a few scattered debris that have apparently been 

 imbedded in the soil. It appears, moreover, probable that the Umestone 

 band either dies out or breaks up into a mass of loose kunkur-like con- 

 cretions, or thin calcareous shales, interbedded in the soft white sandy 

 shales, which are seen in a few wells near the boundary. At Ohenda- 

 mungalum, however, the limestones re-appear in 

 At Chendamungalum. 



the banks of the large square tank of the old fort. 



The beds are thin and irregularly concretionary, and tinged of a yellow 

 color, probably with the ochreous clay derived from the older bed ; their 

 dip is very small, departing but little from the horizontal, and no fossils 

 were discernible : just beyond this the cretaceous beds plunge beneath 

 the alluvium of the Guddalum, and are not again visible to the North- 

 east until we reach (Verdoor) Valudayur. 



At Killanur and Numbakkund a white sand, with a somewhat 

 shaly structure, is seen in some wells not far 



Sand with small fossils. 



from the bottom of the Cretaceous rocks. In this 



soft matrix I found a few casts of small fossils, but the species 



were not recognizable ; they consisted chiefly of small bivalves. A 



similar sand full of casts of small fossils is seen half a mile to the 



East of Chendamungalum. Among them I recognized a Turritella, 



a small Yolutaf a Nucleolite, and a few bivalves, Leda, Solecurtus ? 



and Cytherea. 



That the Cretaceous beds are probably very thin over the whole of 



the Verdachellum area is proved not only by the 

 Thinness of formation. 



low dip of the stratification wherever this is visible, 



but also by the fact that near the Eastern boundary of the Southern 



Cuddalore sandstone outlier a small patch of gneiss, evidently in place, 



is met with about half a mile to the North of the village of Periya 



