448 Geological Society. 



Arts. Also on temperament, the combination or beat note con- 

 troversy, and other matters, very full information is given. 



A trifling point of translation : — The heading of chap. ix. should 

 be, " Depth and Deepest Tones ; " not " Deep and Deepest Tones." 

 And on this subject I say, as I have said before, that none of the 

 experiments here mentioned are comparable for a moment with 

 such experiments as can be made with large open 32 feet organ- 

 pipes, on account of the comparatively enormous amounts of power 

 that can be employed in connection with such pipes. And it can 

 be shown, by a simple process of analysis by beats of consecutive 

 semitones, that the notes of such pipes are generally free from 

 octave, and form something of the nature of sound right down to 

 the lowest notes (16-17 per second). Even with stopped 16's 

 which purport to give the same notes, the fundamentals thus tested 

 generally prove to be absent in the lower octave ; and I cannot 

 believe that with any less amount of power these notes can really 

 be produced in perceptible magnitude. 



This volume supplies the critical student of the subject not only 

 with references up to date, but also with a large amount of new 

 matter. It is a perfect library in itself. 



E. H. M. BOSANQTJET. 



LXI. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 866.] 

 March 24, 1886.— Prof. J. W. Judd, E.R.S., President, 

 in the Chair. 



nHTTE following communications were read : — 



-■- 1. "On the Genus Diphyphyllum, Lonsdale." By James 



Thomson, Esq., E.G.S. 



2. " On additional Evidence of the Occurrence of Glacial condi- 

 tions in the Palaeozoic Era, and on the Geological Age of the Beds 

 containing Plants of Mesozoic type in India and Australia." By 

 Dr. W. T. Blanford, E.R.S., Sec. G.S. 



After recapitulating briefly the principal facts known as to the 

 correlation of the Karoo formation of South Africa, the Gondwana 

 system of India, and the Coal-measures and associated beds of 

 Eastern Australia, and especially noticing those phenomena in the 

 different strata that had been attributed to the action of ice, the 

 author proceeded to describe the additions recently made to previous 

 knowledge by various members, past or present, of the Geological 

 Survey of India, and especially by Mr. R. Oldham and Dr. Waagen. 

 These additions had recently been published in the Records of the 

 Geological Survey of India. 



Mr. R. Oldham, in a recent visit to Australia, had come to the 

 same conclusion as all other geologists who had visited the country, 

 and clearly showed, as the Rev. W. B. Clarke and many others had 

 done, that beds containing Glossopteris, Phylloiheca and Noeggera- 

 ihiopsis were intercalated among marine beds with Carboniferous 



