1 30 LOUIS AGASSIZ. [CHAP. vi. 



by a new process of printing in various tints on different 

 stones ; what has since been termed chromolithography 

 or lithochromy. Nicolet had engaged at Paris a French 

 artist of great ability, Auguste Sonrel, who managed 

 admirably with large plates, and succeeded in printing 

 folio plates with a remarkable uniformity of colouring, 

 as may be seen in the atlas of the " Poissons fossiles." 



The studio for moulding, under the direction of Stahl, 

 a most skilful moulder, was actively at work making 

 casts of the inside of shells and of echinoderms, and 

 also of topographical reliefs of the Jura Mountains, by 

 Gressly, to show their geological structure. 



We must at this time mention an addition to the staff 

 of employes under Agassiz. There was at the meeting 

 of the Swiss naturalists at Neuchatel, in 1837, a verv 

 odd kind of antediluvian or primordial man, so anti- 

 quated that he seemed as if he belonged to the Jurassic 

 period and not to our time ; very awkward, timid, ex- 

 tremely modest, and yet so learned in practical geology 

 that no part of the geology and palaeontology of the Jura 

 had escaped his researches. He knew every topograph- 

 ical feature of the Jura, every group of strata, and almost 

 every kind of fossil remains. With great embarrass- 

 ment he presented to Agassiz a letter of introduction 

 from Jules Thurmann, the great Jurassic geologist of 

 the Bernese Jura, by which Agassiz was informed that 

 the name of the young geologist before him was Armand 

 Gressly. Gressly, in the hurry of the meeting, did not 

 dare to take from one of his large pockets the manu- 

 script of his " Observations geologiques sur le Jura 



