Mr. LyelPs Address. 397 



be very sterile iti fossils. In this respect and in its other characters 

 it agrees with that great calcareous formation described by MM. 

 Boblaye and Virlet in their splendid work on the Geology of the 

 Morea*. According to these French geologists, three quarters of 

 the Peloponnesus are occupied by a compact limestone several 

 thousand feet thick, in which they could discover scarcely any or- 

 ganic remains, except a few hippurites and nummulites, but which 

 is supposed to be the equivalent of our chalk and oolites. Nothingj 

 they say, can be more monotonous in character than this calcareous 

 mass in the South of Europe, which appears to represent the larger 

 part of our upper secondary formations of the North, where the 

 rocks are so varied in lithological aspect and so distinguishable from 

 each other by their well-preserved Ibssils. 



Ancient fossiliferous strata resembling those of the neighbour- 

 hood of Constantinople are said to be largely develoj)ed in the 

 Balkan, a mountain chain of which we may soon expect to receive 

 information from the pen of M. Ami Boue. That indefatigable 

 geologist has already explored a large part of Servia, a country of 

 whose physical and moral condition we are perhaps more ignorant 

 than of any other in Europe, and he is rapidly extending his sur- 

 vey over various parts of the Turkish empire, to the examination 

 of which he proposes to devote several years. Meanwhile our late 

 Secretary, Mr. Hamilton, is continuing, with great zeal, his investi- 

 gation of the borders of the Black Sea and other parts of Asiatic 

 Turkey. 



In a paper on the structure of part of the Cotentin near Cher- 

 bourg, the Rev. W. B. Clarke describes that country as consisting 

 of hills or ridges of quartz rock alternating with valleys of slate oc- 

 casionally associated with syenite and greenstone, which appear to 

 be of posterior origin. A curious fact is mentioned : the quartz 

 rock splits naturally into irregular masses, which have, nevertheless, 

 some angles of fixed dimensions, namely, 103°, 64", and 83". Frag- 

 ments of a green variety of schist exhibit the same angles under the 

 same circumstances of position, proving that similar causes had 

 acted on the two formations en masse, the same sets of joints, lines 

 of stratification, and cleavage being found in both. Besides these 

 facts, which are illustrated by diagrams, the author mentions others 

 calculated to throw light on the cleavage and jointed structure of rocks. 



PROOFS OF MODERN ELEVATION AND SUBSIDENCE. 



Under this head I shall first consider several notices of beds of 

 gravel, sand, clay, and marl, containing recent marine shells, which 

 have been observed in various parts of Great Britain, a subject very 

 frequently brought before our notice of late years. Deposits of this 

 kind have been found by Dr. Scouler in the vicinity of Dublin, 

 where they rise to the height of 80, and in some places of even 200 



* Paris, 1833, in folio. It is to be regretted that this work cannot be 

 procured separately from other folios containing the scientific information 

 collected during the French expedition to the Morea. 



