1834.] Geological Section of the Kasia hills. 293 



new and curious achromatic combinations I have tried. I shall possibly 

 do myself the houour of submitting them upon a future occasion ; mean 

 while, nothing I trust has escaped me in the foregoing observations 

 that can be construed into a disrespectful mention of the Amician 

 reflection. Far from me be the impertinence of disparaging an instru- 

 ment which the highest optical authorities have concurred to applaud. 

 I have merely ventured to inquire whether that instrument, superior as 

 it is, has vet attained the maximum of excellence. 



V. — Notes relative to the collection of some Geological Specimens in the 

 Kdsia Hills betiveen Assam and Nunklow . By W. Cracroft, Esq. C. S. 

 On myjourney from Chira Poonjee to Assam, I endeavoured to recog- 

 nize the ascents and descents, and the geological features of the countrv, 

 as laid down in Captain Fisher's Sketch, but I found this impractica- 

 ble, excepting at those mountains of which he observed the altitudes. I 

 was therefore led to imagine that the intervals between the points 

 given in his sketch had been filled in at random, and that the general 

 geological characters of only the observed points were noted. 



On my return, I endeavoured to obtain a nearer approximation to the 

 real outline of the road, and the positions of the various rocks, and 

 I accordingly made the following notes of the time occupied in travel 

 ling, both in ascending and descending, the different hills, sketching their 

 profile at the same time on the opposite page of my memorandum book, 

 and noting the times and places at which the geological specimens al- 

 ready forwarded to you were collected. The heights of Jyrong and 

 other points I have taken from Captain Fisher, whose barometrical 

 observations have been found to correspond very closely with others 

 since made. Allowance has been made in the outline for the difference 

 of time in ascending and descending. (See PI. XX.) 



First day, from 8h. 48m. ; commencement of ascent to Jyrong. 

 I began to ascend at viii. 48, through a narrow defile ; the rock is 

 apparently a fine grained granite, containing beds of A 2 (a conglo- 

 merate of iron clay) : at viii. 50, reached the bottom of the first descent, 

 (which was a granite similar to No. l.but rather whiter and less decom- 

 posed) : by xi. 7, I reached the next summit, the ascent yielding the 

 granites, A. 4, 5,6, and 7, and decomposing felspar: the road was 

 then comparatively level till viii. 37, when the ascent became steeper 

 and the rock all along was A. 8, (granite) ; but at 37 minutes containing 

 large scales of mica (A. 9.) 



The descent, after ix. 40, was at first very steep, with precipices at the 

 road side : afterwards less steep ; A. 10 and 1 1 mica and gneiss being in 



