Chap. IV.] trichinopoly district — plant beds. 43 



Between Kauray and Terany several good sections of the plant-beds 

 Between Kauray and ^^'^ exposed in the little nullahs that suj)ply Tera- 

 ^^^^^- ny tank. Gneiss all around is much decomposed 



and the joints of the rock frequently filled with kunkur. The bottom 

 bed of the plant-bearing group is variable, consisting sometimes of a 

 red and white speckled sandstone, sometimes of a fine grey shale, and 

 sometimes of a yellow ochreous shale, bearing some resemblance to 

 the beds of the Ootatoor Group. The boulder-bed is here absent. To 

 the east of the old Trichinopoly and Madras road a band of grey sandstone 

 occurs near the bottom of the group, containing large boulder-like calca- 

 reous concretions of a flattened spheroidal form. They so much resem- 

 ble some of the fossiliferous concretions of the 

 Concretion beds. 



Trichinopoly Group, that I examined them close- 

 ly, in the hope of finding fossils, but at this point without success. 

 Crossing over the ridge that divides the catchment basins of Terany 

 and Kauray tanks, this concretion bed is followed by a series of sand- 

 stones and fine compact pipe-clays, with mere traces of plant remains ; 

 and higher up come the usual micaceous shales abounding in the 

 remains of Zamia, &c., and on re-descending from the ridge towards 

 Kauray tank, a somewhat similar though by no means corresjDonding 

 series of beds is crossed over in some of the small drainage nullahs at the 

 eastern edge of Kauray tank, and almost at the bottom of the series some 

 concretions similar to those above described are found jutting above the 

 alluvial soil which has been washed down into the 



Fossils in concretions. 



tank. Some of these I found to be full of small 

 shells, both univalves and bivalves, but for the most part not recognizable. 

 I at first thought that these were probably in situ, although not seen to 

 be embedded, as they occurred just about the boundary of the plant- 

 beds, and were very similar in appearance to the concretions above noticed, 

 near the base of the formation north of Terany ; but subsequent close 

 examination of some specimens which I chipped off, disclosed Cardmm 



