Valhy ofilic Oodipoor. 269 



The basis, or cementing medium, of kunkur, is invariably cal. 

 careous ; and its chemical composition I have found to be very 

 uniform in situations remote from each other. My researches, 

 however, have been confined to the kunkurs of Mewar and 

 neighbouring districts ; and I am not prepared to say how far 

 they may be applicable to the analogous deposits of the rest of 

 India. 



A very common variety of the substance under review is, the 

 " Nodular Kunkur"" of Indian authors. This varies in colour 

 from dirty-white to dark reddish-brown, the nodules are some- 

 times concentric-laminar, externally they have an earthy aspect, 

 but their internal texture is more crystalline, and they are very 

 generally ferruginous. Many of the kunkurs acquire a dark 

 colour on exposure to the atmosphere, some specimens in ap- 

 pearance exactly resemble pisolite, and when the associated frag- 

 mentary particles have been finely comminuted, the mass occa- 

 sionally assumes the character of a calcareous sandstone. When 

 this last includes grains of quartz, crystals of felspar, and 

 other ingredients of disaggregated granitic rocks, it might, by a 

 careless or hasty observer, be mistaken for granite in a partial 

 state of decomposition. The kunkur also assumes various imi- 

 tative forms, and occurs in large irregular masses, and globular 

 concretions. Some varieties are almost compact, with but little 

 of foreign admixture ; others are loose and friable, of a whitish 

 or yellowish colour ; some have a partially oolitic structure, and 

 in one or two situations I have observed kunkur of a regular 

 chalky texture^ appearance, and colour. 



The kunkur beds are not generally stratified ; their most com- 

 mon form is that of irregular and amorphous masses, enveloping 

 the inequalities of the original site upon which they were depo- 

 sited, and frequently exhibiting a corroded surface. In some 

 cases we may occasionally trace appearances of a divisionary 

 structure, somewhat analogous to stratification ; and Captain 

 Franklin has described a conglomerate, which he refers to the 

 kunkur formation, as occurring in horizontal strata. This con- 

 glomerate, he remarks, " when the particles are fine, resembles 

 calcareous sandstone, and has sufficient cohesion for architectural 

 purposes."" 



I have not heard of any well authenticated instances of orga- 



