Correspondence — Professor A. C. Seward. 137 



perpendicular to the plates, through which emerges one of the optic 

 axes. — The question of a relation between Isomorphous Miscibility and 

 Parallel Growths ; \)j T. V. Barker. A study of the growths on each 

 other of immiscible or slightly miscible pairs of substances has shown 

 that although miscibility and parallel growths are favoured by the 

 same factor — similarity and molecular volume — yet the two properties 

 do not always go hand in hand : for many immiscible or only slightly 

 miscible substances form parallel growths quite readily. Mixed 

 crystals, therefore, should not be regarded as built up of alternating 

 parallel layers. — Notes on zeolites from Cornwall and Devon ; by 

 A. Eussell. The occurrence of zeolites in various localities was 

 described, e.g. that of heulandite near Okehampton, stilbite at 

 Botallack and St. Ives, chabazite at Luxullian, apophyllite and 

 analcite at Lostwithiel. — I^ote on the crystallisation of potassium 

 bichromate ; by Professor H. A. Miers. Two stages of growth of 

 potassium bichromate crystallising from a drop of solution were 

 described and illustrated by lantern slides. — On various minerals from 

 the Lengenbach quarry and the Ofenhorn, Binnenthal ; by E,. H. S. 

 Ily. Crystals of binnite, one of them a unique twin, and examples of 

 the regular intergrowth of sartorite and baumhauerite were described, 

 and the occurrence of brookite and molybdenite on the Ofenhorn was 

 for the first time recorded. — Mr. L. J. Spencer exhibited on behalf of 

 Dr. H. J. Johnston-Lavis some minute crystals of haematite found in 

 association with chlormanganokalite in blocks ejected from Vesuvius 

 during the eruption_of 1906._ The crystals have the form of acute 

 scalenohedra /3 {313} = {2461}. A fine series of zeolites from the 

 neighbourhood of Belfast was shown by Mr. F. ]^. A. Fleischmann, 

 a new meteoric stone from Siraondium, Cape Colony, by Dr. G. T. 

 Prior, specimens of reconstructed ruby and blue spinel, and of the 

 new gem benitoite, by Dr. G. F. Herbert Smith, and a specimen of 

 artificial haematite by Mr. C. J. Woodward. 



OOI?,I^ES:E'0:iSrZDEITCE. 



NOTES ON FOSSIL PLANTS FROM SOUTH AFRICA: 

 A CORRECTION. 



SiK, — In the description of Phyllotheca Whaitsi, sp. nov., on p. 481 

 of my "Notes" the locality of the specimen found by Mr. Whaits 

 is given as "Prince Albert in shale lying between the Witteberg 

 Series and the Dwyka conglomerate." I am indebted to Miss Wilman, 

 of Kenilworth (Cape Town), for pointing out to me that the locality 

 should be described as Farm Klipfontein, Fraserburg District, a well- 

 known locality of fossil reptiles. The strata form part of the 

 Beaufort Series, and are probably of Permian age. Miss Wilman's 

 correction is confirmed in a letter from Mr. Whaits. 



A. C. Seward, 



Botany School, Cambridge, 



