156 SCIENCE PROGRESS. 



fessor Bonney to be very indecisive. He objects that the 

 marble cannot be Jurassic, as its lithological characters 

 prove that it belongs to the series of the "upper crystalline 

 schists". He therefore has to explain the way in which a 

 part of the schistose series has been interstratified with the 

 Jurassics ; this he does by assuming that wedges of the 

 older rocks have been thrust up into the newer ones. 

 Cases of this sort of earth movement are now well known 

 in the Belgian coal-fields, so there is nothing impossible in 

 the explanation. But Professor Bonney admits that at 

 Altkircke the wedges "must be unusually long and thin " 

 (p. 291), for they are seen in the tunnel more than 1000 

 feet below the surface, as well as upon it. He admits also 

 that "the general coincidence in strike between the marble 

 and the Jurassic rocks is singular" (p. 297), and that "the 

 stratigraphical evidence seems at first sight favourable to 

 regarding the marble as merely a peculiar member of the 

 group of Jurassic rocks" (p. 286). 



The perusal of this part of the paper does not carry the 

 same conviction as does that of the description of the 

 supposed Jurassic schists to the south of the St. Gothard. 

 When we remember the readiness with which carbonate of 

 lime undergoes crystallisation, it appears quite probable 

 that in the rolling out of some beds of shales containing 

 lenticular masses of limestone the latter should be rendered 

 completely saccharoidal, while the shales have only passed 

 into phyllites. When therefore we hear from Stapff that 

 there are manv beds of this marble alono- the line described 

 by Professor Bonney, and that these are always inter- 

 stratified with the Jurassics, it seems not impossible that 

 they may ultimately prove to be part of this series. 



The question is, however, comparatively a matter of 

 detail. Even if the Altkircke marble prove to be Jurassic, 

 it does not prove the occurrence of Jurassic schists, and 

 does not invalidate the truth of Professor Bonney's main 

 contention. 



The second contribution to this series is the most 

 remarkable of all the papers on the Western Alps that 

 have appeared during the year. It consists of two papers 



