5(5 MIDDLEMI8S : THE GEOLOGY OE IDAR STATE. 



at tight angles to the basal cleavage, and slightly greenish-brown 

 parallel with it. There is a very little sphene here and there dis- 

 cernible. 



From the above description it will be seen that we appeal to 

 have (on a minutely crystalline BOale) a replica of one of 1 he com- 

 monest tvpes of the calc-gneiss such as has already been described 

 from the'Yadali area, e.g. .*/\ (12136), (see pp. 11 to 10), but with- 

 out any microcline or other prominent felspar. 



Specimen No. 4 2 .[\> (12349), a compact, dark, blue-grey limestone 

 with pyrites, from 1 mile N.E. of Malasa. is a. more simple limestone 

 belonging to this series and showing in thin section a very minutely 

 crystalline granular aggregate of mainly calcitc with a little quart/,. 

 The whole appears crushed or bedded along parallel lines. 



The soft, calcareous type of cook, as exemplified in the two 

 specimens quoted above, is only developed m 

 Compact hornstone vorv || ml layers, some few inches across, at 

 uncertain intervals among the thicker beds of 

 the second, more compact, hornstone-like varieties, which in their 

 various shades of pale lilac, drab, -reenish-grey. dark grey and 

 black, make up the bulk of the larger hill-mass. '1 to 3 miles north 

 of Mundeti, and are also well represented in the other little lull- 

 groups. These compact, flint-like rocks are not only fairly hard, 

 but also extremely tough and intractable to the hammer. Many 

 that seem partially homogeneous to the eye, are differentiated 

 under the influence of the weather into fine pastry-like layers ff^ . 

 In some cases the dark and pale grey layers show a semblance of 

 false-bedding 3 2 9 3 jj as regards each other. 



Specimen No. 3 2 J'i (12310) is an example of the pale drab, compact 

 and very tough variety, and is taken from the west end of the 

 1,153 feet peak of the larger hill-mass. Under the microscope it 

 shows a minutely granular structure as a ground-mass, consisting 

 of quartz and a filigree or very delicate skeleton-fretwork of some 

 highly refracting, moderately doubly-refracting granules, more or 

 less connected together and that extinguish together in groups 

 between crossed nicols. These arc utterly shapeless and indistinct, 

 but by analogy with other specimens, they too are probably pyrox- 

 ene. Among this also are larger granules of quartz, often irre- 

 gularly angular in outline and which are entirely separate and not 

 in interlocking areas, and which give the impression of clastic grains, 

 and, by their alignment in parallel layers, suggest a definite bedding 



