534 Dr. T. Sterry Hunt — On Italian Geologt/. 



Gastaldi, written in French, and dated Turin, July 20, 1 878, whicli 

 reached me in London in due time. After reading the first and last 

 pages of this epistle, concerning matters which demanded and received 

 an immediate answer, it was put aside for careful perusal, and by a 

 curious chance was mislaid, and believed to be lost until recovered 

 during the present year (1887). As it is the last recorded word of 

 Gastaldi with regard to various geological problems which had 

 occupied many years of his life, and moreover sustains fully my 

 own opinion formed three years later regarding the rocks in question, 

 as set forth above, I have thought it well to translate into English 

 this precious letter, omitting only those portions which have no 

 reference to the subject before us, — premising that with the exception 

 of the references to the regions then lately examined by him, the 

 conclusions, for the greater part, are already embodied in his 

 previously published papers and in the present writer's summary of 

 them : — 



" Turin, July 20, 1878. 



"Dear Friend and Colleague, — On returning from a long 

 campaign in the Apennines of Prate (Tuscany) and the Apennines 

 of Liguria, I was agreeably surprised to receive your letter from 

 Montreal of June 25, announcing your speedy departure for England. 

 .... I am very glad that you are about to give us a historical and 

 critical work on the Azoic rocks of North America, respecting which 

 it has not been easy to get clear ideas, on account of the extent of 

 the literature and the difficulty of procuring it. I agree with you 

 that we are now enabled to place on a solid foundation the classifica- 

 tion of the Azoic rocks, and you may rely on my support of your 

 views which you will lay before the International Geological Congress, 

 where your skill in exposition will be more effectual, because the 

 facts are evident. I cannot myself attend the Congress, for at that 

 time it is necessary that I should be in the high valleys of the 

 Maritime Alps ; besides which please consider that I am sixty-one 

 years of age, and cannot put off labours which involve great fatigue, 

 and of which I may not be capable another year, , . . 



" You propose to give in your volume my conclusions as to the 

 crystalline terranes of the North of Italy. For this I thank you 

 with all my heart, and demand permission to set forth a summary 

 of my observations.^ As to crystalline ]:ocks, I am even more radical 

 than you ; for me all crystalline rocks are stratified ; for me there is 

 no plutonism ; for me volcanic activity commenced only with the 

 lavas of the Lower Tertiary; at least I know no intrusive rocks in 

 the Alps ; the porphyries there are, to my eyes, sedimentary.^ I 



^ The volume here referred to was that on Azoic Rocks, being Eeport E. of the 

 Second Geological Survey of Pennsylvania, 1878 (8vo. pp. xxi. and 253), and was 

 already printed at that date, a point which I had apparently not made clear to 

 Gastaldi, who sent the notes for the volume in question, as well as for use at the 

 Geological Congress of 1878, where, however, the time had not yet come for their 

 presentation. The volume on Azoic Rocks contains a brief summary of the views 

 of Gastaldi, drawn from his published papers. 



^ I have elsewhere remarked that Gastaldi, misled by his too exclusive "Werner- 

 ianism,^ appears to have included under the name of porphyry both stratified 

 neptunian rocks and intrusive plutonic or pseudoplutonic rocks of more than one 

 kind. 



