172 SCIENCE PROGRESS. 



prolonged action of these, especially when favoured by 

 high temperature and pressure, the author thinks meta- 

 morphosed the marl into rocks which all English geologists 

 would regard as of eruptive origin. Mazzuoli maintains 

 that they cannot be eruptive, because gradual passages 

 from the "argillaceous schist" into the euphotide (gabbro) 

 and diabase frequently occur. He shows one transition 

 from the "argillaceous schist" into the diabase along- the Via 

 di Libiola (p. 7, ii., fig. 3). Neither this diagram, however, 

 nor the paper carry conviction as to the truth of this 

 " anfimorphic " hypothesis of the origin of the gabbro and 

 diabase ; while we even feel certain doubts as to whether 

 the " scisti argillosi " with which they are associated are of 

 so late a date as the Eocene. 



As with Bertrand's paper we notice the same complete 

 neglect of the microscopic examination of rocks. The real 

 difficulties in the passage from a diabase to a clay slate are 

 therefore not considered. The author does, however, give 

 one chemical analysis, but it does not concern the crucial 

 question. Even if it did, we could learn nothing from it, 

 for it starts with an "insoluble residue" of 84*11 per cent., 

 to which nothing further is done, and ends by lumping 

 together the "ferric oxide, water, etc.," which are deter- 

 mined by difference. In this " analysis " less than 10 per 

 cent, of the rock is determined. 



The last paper helps us to realise how different are the 

 points of view from which different schools of workers 

 regard the study of Alpine geology. While in England 

 the igneous origin of gabbro, diabase and serpentine is 

 universally accepted, these rocks are still regarded as 

 aqueous sediments by what appears to be the orthodox 

 school in Italy. Arguments which in England would be 

 taken as final would hardly be accepted in Italy as argu- 

 ments at all. Moreover, the means of research adopted are 

 very different. Thus we find that in some of the papers 

 noticed the use of the microscope is wholly ignored ; and 

 to this neglect of modern methods we have to add in one 

 case an unfortunate provincialism in range, for though the 

 references to literature in it are numerous, these do not 



