588 
gous bone-beds in the Upper Ludlow rock, described by Mr. Mur- 
chison in the ‘ Silurian System’ (p. 198), and in Caldy Island, near 
the junction of the carboniferous limestone with the old red sand- 
stone ; and he offers some remarks on the bone-beds being found in 
all the three cases near the passage from one great geological system 
of rocks to another. 
Among the presents announced at the evening meeting, the Presi- 
dent drew particular attention to a copy of the great Geological Map 
of France, executed by M. Dufrénoy and M. Elie de Beaumont, and 
he expressed the great gratification he felt in reading to the Society 
the following letter :— 
Paris, le 10 Decembre 1841. 
Mownsizeur LE Presipent,—Nous avons eu Vhonneur de vous ad- 
dresser il y a peu de jours, un exemplaire de la Carte Géologique de 
la France et du premier volume de 1]’Explication qui doit Paccom- 
pagner. Nous vous prions de vouloir bien l’offrir en notre nom a la 
Société. La bienveillance avec laquelle nous avons été accuillies 
par la Société et par plusieurs de ses membres lors du voyage que 
nous fimes en 1823 en Angleterre pour en étudier la géologie, nous 
fait ésperer qu’elle accueillera également avec indulgence le travail 
qui nous lui présentons. Nous n’oublierons pas que les belles dé- 
couvertes faites en Angleterre sur les terraines stratifiés nous ont 
servi de modéles dans |’exploration que nous avons fait de la France, 
et nous remercions les membres de la Société qui ont bien voulu 
nous initier a l’étude de la géologie Anglaise de l’appui quils nous 
ont preté dans nos travaux. 
Veuillez, Monsieur le Président, etc.,; 
Durrenoy. 
Ere pe Beaumont. 
To this letter the following answer was addressed to M. Dufrénoy 
and M. Elie de Beaumont by Mr. Murchison :— 
Geological Society of London, Somerset House, 
December 16, 1841. 
GENTLEMEN,—At a meeting of the Geological Society of London 
held yesterday, I had the honour to present, in your name, the copy 
of your great Geological Map of France recently received by us. 
On that occasion I read the letter of the 10th instant with which 
you had honoured me, and I characterized it as containing the 
highest compliment which has been conferred upon the Geological 
Society of London since my connexion with it. To learn from such 
truly eminent geologists, that the principles of classification of the 
sedimentary rocks of England, as formerly studied by yourselves 
in eur island, had led you tu undertake the splendid work which you 
have now so successfully completed, is indeed the highest tribute 
which the practical geologists of Britain can receive. 
I have directed your letter to be inserted in our Proceedings, 
whilst on my part I beg to assure you, that I shall seize the oppor- 
