428 



Scientific Geology. 



from Northampton to Hartford, the following 1 case occurs in the new 

 red sandstone. A deposit of greenstone, the remains of a large vein 

 or protruding mass, is here seen to lie in an oblique direction upon 

 the elevated edges of the sandstone. Towards the upper part of the 

 section, the layers of sandstone are curved considerably upwards, so as 

 to increase the dip of their upper extremity, raising it, indeed, almost 



coming cellular near its point of contact with the schist. Does any such phenom- 

 enon occur with you 7* 



Transition Schist. 



" Since I had the honor of writing- to you, I have continued without intermission 

 to collect facts for my work on the Basalts. But it will be a long- time before I 

 can bring- it to a conclusion. In 1828 I visited Auvergne. This without contra- 

 diction is classic ground as to this matter. You are doubtless acquainted with 

 the work of Scrape, (Central France.) But I have ascertained some hew and quite 

 interesting facts. Among others the projecting mass of basaltic conglomerate 

 which rises through the beds of lacustrine limestone, (it bears the name of Puy de 

 la Piquette,) embraces fragments of that limestone full of many fine crystals of 

 mesotype and apophyllite. Last summer I visited the Suabian Alps. In these 

 mountains we find a number of important facts. We count there at least thirty 

 eruptions or elevations of basaltic breccias through the beds of Jura limestone ; 

 and these conglomerates contain a number of small fragments of limestone, which 

 have been variously modified by the heat of the conglomerates. 



" Finally, I pray you to preserve in full, an account of the phenomena of basalt, 

 diorite, and amygdaloid, as well as of the conglomerates which accompany them ; 

 and I would request you to send me these details. 



* * * * * * 



" I have the honor to salute you with the greatest respect : 



" Yours with devotion, 



LEONHARD." 



* Precisely the same, as I shall mention more particularly farther on. 



