260 
The unhappy circumstances of the country have long abstracted 
the attention of the Spaniard from researches of science, and the dif- 
ficulties of travelling in the midst of civil commotions have deterred 
even the enterprising spirit of neighbouring geologists from endea- 
vouring to fill up the lamentable blank which Spain still presents 
upon the scientific map of Europe. 
Brigadier Silvertop, though occupied in the professional engage- 
ment of arms, was not forgetful of the pursuits of science. He pub- 
lished the substance of his communications to this Society in a small 
volume, 1836, wherein he gives a sketch of the widely-disseminated 
deposits of tertiary beds in the provinces of Granada and Murcia, 
accompanied by a general view of the volcanic and other rocks of the 
same district, illustrated by sections, which represent the configura- 
tion of the ground, the relative height of the ridges, and the super- 
position of the strata. He died at Rennes, in June last, on his way 
to the Pyrenees and Italy. 
Mr. Louis Hunton was the author of a paper printed in our 
Transactions on the Upper Lias and Marl-stone of Yorkshire, 
showing the limited vertical range of the species of Ammonites and 
other Testacea, and illustrating their value as geological tests. His 
observations are founded on the details of the section of Easington 
height, near Whitby. 
Jens Esmark, Professor of Mineralogy in the University of 
Christiania, was one of the many disciples of the school of Frey- 
berg, who imbibed from their master an enthusiastic devotion to his 
theories, which largely contributed to stimulate into activity that ge- 
neral spirit of geological inquiry, the expansion of which, during the 
present century, has produced such unexpected and extensive dis- 
coveries in the development of the structure of the earth. 
In 1794, deeply imbued with the doctrines of Werner, he went 
to Vienna to prepare himself for a tour through Hungary; after 
this he remained some months at Chemnitz, and visited the other 
chief mining districts of Hungary, Transylvania, and the Bannat, 
and crossing the Carpathians to Wielitzka and Cracow, returned 
to Saxony by the mines of Tarnovitz in Silesia. 
In 1798 he published, at Freyberg, the result of his observations, 
in a small octavo volume, giving descriptions of the mines he visited, 
and their respective productions, and expressing his conviction of 
