On the Physical Features of Saturn and Mars. 203 



the newer boulder clay, or do they occur at more than one level, 

 as at the top, the middle, and towards the bottom of the older 

 deposit 1 The conditions necessary to the formation of glaciers, 

 and to that of the boulder clay, are apparently so different, that 

 we can scarcely suppose them to alternate. The few facts 

 known to me, however, rather favour the idea that they did 

 alternate, or at least that the striated blocks occur at more 

 than one level ; but information is yet wanted on the subject. 

 Mr Robert Chambers, in a paper published two years ago, 

 expressed an opinion that the mounds A B were probably parts 

 of a lateral moraine of the glacier of Corusk valley, I con- 

 sider this opinion altogether untenable ; but as I learn from 

 •him that he has subsequently renounced it, nothing more need 

 be said upon the subject. 



Note. — The description of the moraines in Glenmessan is the substance of a 

 communication made viva voce to the Geological Section of the British Associa- 

 tion, at the meeting in Edinburgh in 1850. But the discussion commencing at 

 the foot of page 198 is an addition. 



Physical Features of Saturn and Mars, as noted at the 

 Madras Observatory. By Captain W. S. Jacob, H.E.LC. 

 Astronomer. (With Two Plates.) 



Saturn. 

 Our knowledge of the physical features of the planet Saturn 

 has received several important additions within the last few 

 years ; an eighth satellite discovered almost simultaneously in 

 America and England, by Bond and Lassell, — the inner ob- 

 scure ring, also seen about the same time by Dawes and Bond, 

 — and the fine line or division in the outer bright ring ; these 

 are the most notable points that have been brought to light. 

 The last two are not, indeed, strictly speaking, recent discover- 

 ies, since the obscure ring would appear to have been seen, 

 and even some measurements of it made, by Dr Galle of Berlin 

 in 1838, while several observers have at different times seen, 

 or imagined they saw, one or more lines or markings on the 

 outer ring. A notice by Captain Kater of such appearance, 

 accompanied by drawings, is to be found in vol. iv. of the 

 Memoirs of the Royal Astronomical Society. But these ob- 



