Miscellaneous. 75 



equivalent to the English lias. On the face of the Cherra mountain 

 the green marl rests unconformably on old red sandstone (or that on 

 which the coal formation rests), and gives support to the deposits of 

 sand in which the marine remains are contained. It is here by no 

 means destitute of fossils as in other localities ; on the contrary, we 

 found in it six species of univalve shells, a small species of Echinus 

 and a large spined Cidaris. In a note which we made on the cha- 

 racters of a fragment of rock brought away from a submerged reef 

 near Arracan, by the hull of a ship which struck upon it, we pointed 

 out the resemblance between its appearance and that of the green 

 conglomerates in question*. 



" A description of the salt formations at the head of the Indus, and 

 their relative position to the coal-measures recently found there by 

 Mr. Jameson, will be the means of casting much important light on 

 this subject in regard to India, and we have fortunately in the gen- 

 tleman alluded to a geologist near the spot, fully alive to the import- 

 ance of this and other questions of a similar nature. Another equally 

 important question is the situation of the great repositories of salt in 

 the vicinity of Ajmeer and other situations in Central India, where 

 salt lakes abound. Lieut. Fraser, of the Engineers, we recollect, 

 sent us a fragment of rock-salt, which was found imbedded in a ba- 

 saltic rock when sinking a well at Mhow, about three feet from the 

 surface. We have not heard that this curious fact has led to any 

 further discovery or research in the neighbourhood alluded to. 



" It would be extremely important if we could establish good distin- 

 guishing characters between the limestone of the coal-measures and 

 that of the more ancient formations, but this, if a matter of difficulty 

 in England, is at least an equally difficult thing in India. It is true, 

 the subject has here been as yet little investigated, but we cannot 

 place the least confidence in those practical men who employ names 

 without thinking of their meaning, and speak confidently of lias, 

 and carboniferous limestone, primitive limestone, &c, according as 

 they happen to suppose any particular specimen they meet with in 

 India to be one or other. The limestone so abundant in Kemaon, 

 as to form the greater portion of that mountainous district, is so much 

 like the limestone of the coal-measures at Cherra Ponji, that no one 

 unacquainted with the peculiar relations of the two rocks would sup- 

 pose them to be at all different. The geologist, however, perceives 

 the vast difference between them at once : the one reposes on clay- 

 slate, the other on sandstone ; the one occurs in thick continuous 

 beds, the other alternates with shale ; the one abounds in fossils, 

 which scientific men alone would think of looking for, and in the 

 other the geologist alone would know that he might look for fossils 

 in vain. Speaking of the difference between the limestone of the 

 Silurian system and that of Coalbrook dale, Mr. Murchison says, that 

 the organic remains, which are in great profusion in the latter, con- 

 sist of shells and corals which are characteristic of the carboniferous 

 limestone in many other parts of Great Britain, and never occur in 

 * Journ. Beng. As. Soc. 1838, p. 936. 



