298 PROF. T. G. BONNET ON MESOZOIC KOCKS AND [Aug. 1 894, 



very well exposed, but the former (here a calc-schist) is much 

 crushed and quartz-veined. 1 Prof. Heim denies that the section 

 affords any evidence of thrust-faulting. What constitutes evidence 

 is a question on which different opinions may be entertained. I can 

 only say that I have not often seen anything more suggestive of 

 thrust-faulting than the condition of the rocks just at the junction 

 of the schist and rauchwacke, 2 and in such matters I am by no 

 means a novice. 



Our section, made in 1889, exhibits three bands of black-garnet 

 schist wbich differ in thickness. On this occasion I could find only 

 two, one being buried beneath the debris. The higher was a little 

 more than 60 feet (vertical) below the top of the mass of schists, 

 the lower approximately 20 feet above the bottom. 3 A comparison 

 of my notes made on the two occasions leads me to the conclusion 

 that the missing band is the middle one in the published section. 4 

 If so, it is for those who advocate the hypothesis that the schists 

 and rauchwacke form a simple trough of Mesozoic rocks to account 

 for this difference in the distances of the black-garnet schist from 

 the bottom of the said trough. In any case, how are we to explain 

 the presence of three bands of that rock? There may be 'luck in 

 odd numbers,' but they are out of place in a transverse section of a 

 simple trough. Prof. Heim cannot appeal to a fault to remove 

 the difficulty ; for if once he lets a fault ' in at the door,' he will 

 find that the Jurassic hypothesis ' flies out at the window.' 



On this occasion I examined more minutely and for a greater 

 distance the schists above the upper mass of rauchwacke. It is, 

 however, needless to give all the details. A ' distheue-schist,' which 

 differs so slightly from those in the group of schists below, that with 

 a little more crushing it would be indistinguishable, occurs more 

 than once, and, from about 30 feet vertically above the top of the 

 rauchwacke, bands of it are associated with gneiss or mica-schist 

 containing actinolite. 5 About 10 feet above the rauchwacke is a 

 garnet-bearing schist which macroscopically reminds us of the black- 

 garnet schist 6 already mentioned, though the garnets are red and 

 the mica is much more ' silvery.' But in other localities I have 



1 This is within about a dozen feet of undoubted rauchwacke. So greatly are 

 the rocks ' troubled ' near the actual junction that it is difficult to determine 

 whether a very small outcrop in the interval is crushed schist or crushed 

 rauchwacke, but I think it is the former. The latter rock hereabouts contains 

 very small bits of silvery schist with clastic mica-flakes, but no large fragments 

 as it does at the top of the higher mass. 



2 As stated in my paper (Quart. Journ. Geol. Soc. vol. xlvi. p. 209), I do not 

 consider this to be the only evidence of thrust-faulting. 



3 It was 230 feet from the top. The junction of the schist and lower rauch- 

 wacke, as said above, cannot be determined with absolute precision. 



4 Op. supra cit. p. 210, fig. 5. 



3 That is, with rocks of the type to which, for descriptive purposes, I have 

 given the name of the ' Tremola schists.' 



6 Op. cit. p. 209. My observations on this occasion made me doubtful as to 

 the existence of a fault between these rocks and the ' Tremola schists ' — the 

 uppermost one in fig. 6, op. cit. p. 210. Its presence or absence is immaterial 

 to the main question. 



