of the Lepontine Alps. 15 



referred to in tlie " Zeitsch. d. deutsch. geol. Gesell." 1878, p. 138, 

 as follows : " Only in Nos. 43 and 45 have those puzzling micro- 

 scopic structures been noticed, of which I sent a drawing to Prof. 

 Desor, 26th Feb. 1877, and to which I drew the attention of Prof. 

 Zirkel by letter of 29th Oct. 1877. In the text to the geological 

 profile (German, p. 22 ; French, p. 24) they are described as blackish 

 indistinct points (pores) arranged in rows, so as to form four-rayed 

 stars by their intersection at right angles to each other. Professor 

 Giimbel, who examined my slides, declared them to be unequivocally 

 structures of crinoids, and this accords with the occurrence of 

 circular or elliptic sections of crinoid stems in the cipolines, both 

 inside and outside the tunnel (Ruestli ; heap E. from Altkirche). 

 The woolly threads of graphite in No. 45 are partly grouped in 

 polymorphous net-works, one of which I have copied in Zeitsch. d. 

 deutsch. geol. Gesellsch. vol. xxx. 1878, p. 138. No palaeontologist 

 Vi^ho has seen this slide has doubted the organic nature of the form 

 contained in it ; but the interpretations of its character have varied 

 between corals, sponges, and bryozoa — Prof. J. Hall inclines to this 

 latter view of their origin. 



I believed the question of the organic character of the fragments 

 in this highly crystalline micaceous limestone to have been settled ; 

 but finding that Prof. Bonney {loc. cit. p. 198, footnote) declared 

 them anew to be pseudo- or gamo, I submitted the slides to Professor 

 Mobius, Director of the Eoyal Museum at Berlin, so well known for 

 his investigations on the structure of Eozoon, and he has given me 

 permission to state that " these forms in Ms opinion are of organic 

 nature, so far as can be judged from a hasty examination of only tico 

 slides, without comparing them with analogous structures." I have 

 lately had taken microscopic photographs of the structures in the 

 slides referred to, Nos. 43, 45, and the accompanying figures have 

 been reproduced from them by autotypic process (see p. 16). 



With regard to No. 45, I may remark that the light gray cross 

 lines of the net-work seem in part to follow the cleavage faces 

 through the calcspar, and would thus agree with Prof. Bonney's 

 description of crinoidal microstructure in preparations from Scopi 

 (loc. cit. p. 234-35). If No. 45 should beget any scruples as to its 

 real nature, they would not affect No. 43, in which the black points 

 and blisters are arranged in slightly curved lines, which intersect 

 one another at angles of about 80° and 100°. 



Though these microscopic traces of organisms in the Altkirche 

 cipolines indicate the existence of crinoids, which were already 

 known macroscopically and are without special value for the fixation 

 of geological horizons, yet they are of great general interest as 

 showing how the structure of fragmentary Jurassic fossils can be 

 preserved in highly metamorphic micaceous limestone. It is now 

 fourteen years since they were first noticed. 



V. Classification of the crystalline schists in the St. Gothard (and 

 their relation to the Mesozoic rocks). — The first arrangement of the 

 beds passed through in the St. Gothard tunnel, which I sketched in 

 the " Neues Jahrbuch fiir Mineralogie, etc.," 1878, has since re- 



