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Sketches of (he Meteorology, $c. 



and mode of disintegration, to the different appearances alluded to. 

 The most common variety appears to be the carved laminar; the 

 lamina? varying in their thickness from a few inches to many feet, and 

 almost infinitely in the degree of their curvature. The bare mammil- 

 lary shaped hills and knolls, which are so common throughout the 

 granitic tracts of India, owe their origin to the curved laminar struc- 

 ture of the granite. They have almost invariably loose angular plates 

 resting on their sides, which have arisen from the most superficial of 

 the laminae having split, and separated from those beneath*. 



The laminae are sometimes straight, but seldom to a great extent ; 

 for if traced to a short distance, it will generally be found that they 

 soon lose their straight direction, and become curved. These straight 

 lamina? (as might be expected) vary in their dip, from horizontal to 

 vertical. 



The granite, on one side of a small hill at Shawpore near the Beema, 

 has somewhat the appearance, when seen in a certain direction, from a 

 little distance, of being columnar; but when it is examined more 

 closely, it becomes evident that this appearance arises from the follow- 

 ing circumstance. The laminae of the granite, on that side of the hill, 

 are straight and vertical, and had formerly made a very rapid curve at 

 the top. By the influence of the weather, the curve had been worn 

 away, and had thus allowed the inferior vertical parts of the laminae 

 to separate a little from each other ; and, accordingly, when seen trans- 

 versely, they have somewhat of a columnar appearance. 



The laminae of the granite are very often divided by natural joints or 

 seams, which, in some instances, give rise to an obscure prismatic 

 structure. These seams becoming widened by the action of the 

 weather, and many of the separate masses, owing to their more perish- 

 able nature, having been disintegrated and removed, many of the pecu- 

 liar features of the granite, already described, are thus produced. 



A very interesting variety of these seams is met at Chundergooty, on 

 the north-western frontier of the Mysore country. A small range of 

 low undulating hills is composed of the common curved laminar 

 granite ; the laminae of which vary from several feet to a few inches in 

 thickness. Parallel to the direction of the range, namely, south by 

 west, the granite is divided by vertical seams, which maintain the most 

 perfect parallelism throughout their whole extent ; and thus, were we 

 to leave out of consideration the laminar structure, they might be said 

 to divide the hill into regular vertical strata. The superficial laminae 

 have, in many places, separated at the seams, and by exposing those 

 below, have afforded a proof that the seams extend through the whole 



* Bellary hill, some of the hills at Anagoondy, and Moid Alley hill, near Secunderabad, 

 are good examples of these appearances, 



