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PROF. T. G. BONNET ON MESOZOIC ROCKS AND [Aug. 1894. 



project slightly on weathered surfaces, are interstratified with more 

 argillaceous layers. On the southern side rauchwacke occurs in 

 irregular patches of no great thickness, being apparently not always 

 present. On the northern side of the belt the junction of the phyllite 

 and gneiss is exposed, though it is not very clear, for it is much 

 troubled by quartz-veins. So far as I could see, the phyllite became 

 rather sandy for the last few inches, though it did not contain 

 visible fragments, and the gneiss was exceptionally crushed. On 

 the southern side ' sericite-gneiss ' crops out, and can be certainly 

 identified within a short distance of the phyllite. It is possible 

 that here also the junction is exposed, but in this place the rocks 

 are so much crushed that I refrain from expressing a positive 

 opinion. In this section I could find no trace whatever of the 

 Altkirche marble, for even the most crystalline seams do not 

 resemble it, but they reminded me rather of the matrix in some of 

 the Jurassic knotenschiefer of the Nufenen Pass, etc. 1 



(b) Sections on the lower slopes of the Oheralp. — Some of these 

 were described in my last paper, but, as I carefully re-examined the 

 whole slope between the northern gneiss and the marble, clearing 

 up some minor details and making one important discovery, I shall 

 venture to describe it rather fully, though this involves a certain 

 amount of repetition. Time will be saved by regarding this section, 

 or rather group of sections, as a whole, and commencing the de- 

 scription at the back of the old church, some 40 or 50 feet above 

 the high road of the St. Gothard (fig. 1). On the northern side is 



Pig. 1. — Section at Altkirche : length rather less than | mile. 



N. S 



1 = Micaceous gneiss. 



2 = Phyllite (Jurassic ?). 



3 = Marble. 



3'= Second mass of marble. 



4 = Phyllite, etc. (Jurassic). 



5 = ' Sericite-gneiss.' 



6 = Phyllite (Carboniferous). 



7 = Hospenthal schists. 

 x = Covered ground. 



the gneiss, as usual, which runs up the steep mountain-slope, often 

 terminating in a low crag, overlooking a slight depression. The 

 latter is occupied, as already stated, by a dark phyllite, which can 

 be seen cropping out within a few feet of the gneiss : the cleavage, 

 which is nearly vertical, striking a little E. of N.E. The depression 



1 Confirmed by examination of one of the most crystalline-looking pieces 

 under the microscope. Fragments occur with traces of organic structure, 

 probably crinoidal. 



