GEMS FEOM PEIVATE COLLECTIOXS. 



315 



will sliow tliat out of forty-three species wliicli I enumerate as British, 

 tliirfcy-five occur in Belgium, viz., Spirifera striata, 8. Mosquensis, 8. 

 humerosa, 8. diiplicicosta, 8. crassa, 8. hisulcata, 8. grandicostata, 

 8. trigonal Is, 8. convoluta, 8. triangularis, 8. mesogonia, 8. laminosa, 

 8. distans, 8. cuspidata, 8. jpinguis, 8. ovalis, 8. ijlanata, 8. integri- 

 costa, 8. tdradialis, 8. rhomhoidea, 8. lineata, 8. TJrii, 8. glabra, 

 8. odoplicata, 8. insmlpta ; Gyrtina s&ptosa ; Atlmjris ploAWstdcata, 

 A. lamellosa, A. Boysii, A. squamosa, A. glohtdaris, A. amhigua, 

 A. suhtilita ; Retzia radialis, R. idotrix ; and that Belgium possesses 

 ten or eleven species which do not occur or have not hitherto been 

 discovered in our British isles, namely, 8pirifera pectinoidea, de Kon. ; 

 8p. ornata, de Kon. ; 8p. Fischeriana, de Kon. ; 8jp. acuticostata, 

 de Kon. ; 8p. Roemeriana, de Kon. ; 8p. 8clmuriana, de Kon. ; 8p. 

 ventricosa, de Kon. ; 8p. glaherrima, de Kon. ; 8p. clieiropteryx, 

 de Yerneuil ; 8p. Bronniana, de Kon. ; and Retzia serpentina, de 

 Kon. Many new and original ideas regarding the stratigraphical 

 distribution of the species by that distinguished Belgian savant are 

 also there introduced, to which I would recommend the attention 

 of those who may feel interested in the subject. 



In an illustrated catalogue of all the Scottish species of car- 

 boniferous Brachiopoda at present known, now preparing for The 

 Geologist, I shall have occasion to revert to the two contempo- 

 raneous (?) carboniferous faunas discovered in Belgium by Prof, de 

 Koninck, which he has designated as the Fauna of Vise, and the 

 Fauna of Tournay, and which he believes to have recognized also in 

 Great Britain. 



THE SPIRIT OF GOOD BOOKS, 



ON LAVAS OF MOUNT ETNA FORMED ON STEEP 

 SLOPES AND ON CRATERS OF ELEVATION. 



By Sir Charles Ltell, F.R.S., D.C.L. : London, 1859. 

 {A Paper read before the Royal 8ociety, lOtJi June, 1858.) 



For some years past it has been a commonly received doctrine 

 among continental geologists that lava-streams could not consolidate 

 on slopes or declivities of more than five degrees. When, then, solid 

 lavas were found in various volcanic mountains at high angles, other 

 sources of origin than the mere outflow from their respective craters 

 had to be sought ; and thus arose the theoretical idea of the formation 

 of the cone or crater at a late period of the volcano's existence — 

 after for ages numerous lava-streams had issued from it and had 

 become consolidated one over the other into stony beds on successive 



