318 



On the Geology of Cutch, 



[Oct. 



Relative Position with respect to the other Strata. — 1 searched diligent- 

 ly to find the relative position of this formation distinctly defined, but in 

 rain, as, at its apparent junction with other beds, the whole of the strata 

 were broken up, and so confused as to baffle every attempt to ascertain 

 the boundary. I am induced, however, to believe that it occupies hol- 

 lows in the sandstone and coal formation, or abuts against it. It cannot 

 underlie that series, because its strata are always horizontal, except 

 where locally disturbed ; while the beds of sandstone and coal are as in- 

 variably inclined at a considerable angle, and are everywhere intersected 

 with dykes, slips, and other dislocations, from which the upper secon- 

 dary strata are generally free. In one instance the formation evidently 

 occupied a hollow in the coal sandstone. 



In many places it appears to abut against the sandstone, occupying 

 large tracts which may, at some period, have been covered by beds of 

 that formation, subsequently washed away. From what has been stated 

 above, it is at all events newer than the coal beds ; and this conclusion 

 is also borne out by its imbedded fossils. 



Apparent Position wilh respect to the English Series. — In its mineralo- 

 gical character and general appearance, this formation greatly resembles 

 the English lias ,* but its fossils have been found, after a careful exami- 

 nation by Mr. James Sowerby, to assimilate very closely to those of the 

 oolitic beds ; and a very few belonging to the green sand. 



Fossils. — Of the fossils found in these beds, the Ammonites are the 

 most characteristic, occurring in vast quantities, particularly in some 

 hills bordering the Runn. Of the eleven species which I collected, 

 eight are unknown to Mr. James Sowerby, to whom I am entirely indebt- 

 ed for all my informatioii regarding them. Of the other three species, 

 one so closely agrees with A. Herveyii of the Eaiglish cornbrash, that 

 he is induced to consider it only a variety of that species ; another in 

 the outer whorl resembles A. perormatus of the coral rag, but differs in 

 the structure of the iimer whorls ; and the third, of wh^'ch there is only 

 one imperfect specimen, is like A corriigatiis of the inferior oolite of En- 

 gland. They generally vary in diameter, from three to five inches : the 

 largest I found being tight inches. It was inibedtled in a mass of gold- 

 coloured oolite. The genus next abundant is the 'J'erebratuia. Of the 

 rsevcn species collected by me, five bear so close an analogy to the T. 

 bipUcata, T. dimidiatn, T. sella, T. intertvedia, and T. concinna of the 

 green sand and oolitic scries, that it has been found impossible to con- 

 sider them distinct species. The Trigonias are numerous, though con- 



