22 GEOLOGY OF TIUGIIIXOI'OLY, & ■, [ClIAP. I. 



alluvial soils near to the sea and to rivers, where of course the soils are 

 true sedimentary deposits. The resemblance of some of these to the 

 Loess of the Rhine is alluded to. The occurrence of basalt near the 

 Vellaur river is noted, but the gneissic rocks adjoining are erroneously 

 regarded as granite. 



In speaking of the western part of Trichinopoly district, Mr. Muzzy 

 alludes to a " small mountain'^ made up in part of magnesite, brucite, 

 and other magnesian compounds. This is probably a reference to the 

 magnesite veins occurring at Cajareputty, and described in this report 

 further on. The great band of chloritic rock near Cunnanoor also came 

 under his notice, though, strange to say, he appears not to have met 

 with the great magnetic iron beds occurring in that immediate neigh- 

 bourhood. Limestones occurring on the banks of the Cauvery near the 

 upper anient are alluded to but cursorily as of a Verde- Antique variety of 

 marble. These are probably the beds of limestone discovered during the 

 progress of the survey at Mootum and Naivailie on the banks of the 

 Jyaur, which falls into the Cauvery just above the anient at the head of 

 Seringham Island. Mr. Muzzy refers fiirther to magnesian rocks as occur- 

 ring near Volcondapuram, in the northern part of Trichinopoly district, 

 but does not describe them nor explain their relations to the metamorphic 

 rocks upon which they rest. While correctly describing the granite veins of 

 the left bank of the Cauvery as porphyritic in character, he has been misled 

 in regarding the hornblende schists, which are very largely developed 

 in that quarter, as syenitic granite. In speaking of the countiy south 

 and south-west of Trichinopoly, the felspathic gneiss is treated as a por- 

 phyritic granite. Mr. Muzzy^s notices of the cretaceous rocks, which 

 are much fuller than those just alluded to, have already been referred to 

 by Mr. Blanford in the first part of this volume. 



In the summary of the Geology of India by Mr. H. J. Carter, of 

 the Bomljay Medical Service, appended to the " Geological Papers on 

 Western India" edited and published by that Officer in 1857, a few 

 ( 2-14 ) 



