Chap. YI.] trichinopoly district — ootatoor group. 85 



Kolokaunuttom and Shutanure, it rather increases than diminishes), it would seem that 



the increase in the width of the out-crop is due solely to the increased thickness 



of the group, a thickness which has more than doubled itself in a distance of 7 miles. 



That the phenomena are more satisfactorily explained otherwise I shall, however, endeavor 



to show in the sequel, and in the meantime will return to the detailed description of the beds 



in question. 



A little nullah that runs "Westwards into the "Western extremity of Terany tank lays bare 



some of the bottom beds, althouah to no great extent. Thev consist 

 Bottom beds at Terany. j o o j 



of unfossiliferous shale and clay, with intercalations of brown sand- 

 stone, and when close to the gneiss a few irregular patches of conglomerate, the latter cemented 

 into gi-eat calcareous blocks that range horizontally over the surface. The shaly bands appear 

 to roll somewhat at low angles (5° to 10°) but with no regularity, and as this phenomenon is 

 common in the lower beds, and there only, and is never accompanied by any evidence of fracture, 

 I have every reason to believe that it is owing to irregiilar deposition and the unevenness of 

 the gneiss bottom. 



The conglomerate contains pebbles of gneiss and coral-reef limestone, together with a few 



fossils, Astrcea, ^-c, but chiefly undistingmshable, and some small 

 Conglomerate. 



fragments of exogenous wood. 



At this point the boundary is very ii-regular in outline, owing apparently to what I have 



Beds East of Terany. above noticed, viz., the irregularity of the gneiss surface on which 



the beds were deposited. A narrow promontory of gneiss runs in 

 to the Eastward for about half a mile, and at the extremity, which is very steep, and is exposed 

 in some broken ground on the East of the watershed, the Ootatoor beds are seen resting at high 

 angles partly on the gneiss and partly on the plant shales which here crop out from beneath 

 the first-named beds. 



This locality has been already noticed at page 42. The Ootatoor beds are clays and shales, 



Enclosed fragments of plant "«^itiiout any conglomerate, except that, at one place, some of the 

 ^^^^^^- shale bands are full of little angular fragments of the soft plant 



clays, which being softer than the enclosing matrix, are rapidly washed out from exposed 

 Surfaces, leaving the shale full of small irregular cavities. 



This is almost the only instance in which I have met with fragments of the plant -beds in 

 any of the newer rocks, a fact undoubtedly owing to the slight consolidation of the former, 

 and the ease with which they would be reduced to sand or mud by attrition. The way in 

 which these beds have been denuded from the Southern flank of the gneiss promontory, while 

 they have been preserved in the North up to its extreme point, is undoubtedly due to the protec- 



Cause of unequal denuda- *^°^ afforded by it, and indicates that at the period of denudation, 

 tiou of plant-beds. j_ g_^ ^^ ^^^ previously to the commencement of the Ootatoor 



period, the prevalent current or Avind which determined the denudation at this point must have 

 operated from the South-west. 



The fossils here met with are those characteristic of the Ootatoor clays, viz., a few Ammonites 



Belemnites, and the conoidal Annelid. Kunkur and Gvnsum 



Fossils and minerals. ^ ^ ^^ 



abound as usual. To the Northward, as far as the limestone 



of Kauray, and for about a mile and a half or two miles to the Eastward, beds of similar 



character prevail. The dip, when apparent, is irregular, with a general tendency to the East. 



The loose structure of the beds is very unfavorable to observations on this point, and although 



surfaces, dipping at considerable angles, ai-e sometimes met with, I believe that they ai-e due 



