164 



7. The coal-formation and other subjacent beds are not consi- 

 dered in the present paper; the author referring for an account of 

 them to the works of local geology already published or in progress ; 

 and to the paper on the Environs of Bristol, by Messrs. Buckland 

 and Conybeare, (Geol. Trans. 2nd series, vol. i.) for a description of 

 the analogous portions of England, which may perhaps remove 

 some of the difficulties connected with the corresponding formations 

 in the Low Countries. 



The chief points of difference then, between the formations above 

 referred to and their equivalents in England, are — 1. The apparent 

 identity of the fossils in the sands above the chalk, with those which 

 appear in the clay of London. — 2. The Maestricht stratum, dis- 

 tinctly superior to the chalk, and differing from that bed in its 

 fossils and other characters, is without any equivalent yet ascer- 

 tained in this country; but some facts are mentioned, which show 

 that the former existence of such a stratum above our chalk is not 

 improbable, and that further traces of it may still be discovered upon 

 sufficient search. — 3. The hard beds (of Cunroot,&c.) form a remark- 

 able feature of the lower chalk in the country above described. — 

 4. The absence or indistinctness of the gault, is one of the principal 

 circumstances distinguishing the green-sand formation from ours ; 

 and the want of a valley, like that which commonly exists in this 

 country along the foot of our chalk-hills, is an important difference 

 of external feature. — 5. The entire absence of the formations which, 

 in the south east of England, succeed the green-sand (theWeald clay, 

 Hastings sands, and Purbeck strata), deserves also to be mentioned ; 

 for, of these beds, though so fully developed on our coast, none have 

 yet been distinctly recognised upon the Continent, and traces only 

 detected in the interior of England and in the lower Boulonnois. 



In conclusion, the author remarks upon the great diversity of the 

 upper and unconformable formations which, in different places, are 

 in immediate contact with the older and inclined strata beneath. In 

 some cases (as near Bristol) the red marl, lias, and lower oolite; — in 

 others (lower Boullonois) the upper oolite; in others still, the green- 

 sands, the gault, and even the chalk itself, — are in contact with the 

 coal strata. It may be difficult to explain the cause of this variation, 

 and to account for the absence of the beds which are wanting; for 

 the upper formations bear no obvious marks of disturbance, and are 

 generally horizontal or very little inclined. 



Jan. 1, 1830. — The Rev. Henry Coddington, of Trinity College, 

 Cambridge, was elected a Fellow. 



A paper was read, " On the Geology of the shores of the Gulf of 

 La Spezia;" by Henry Thomas De la Beche, Esq. F.G.S. F.R.S. &c. 



The chief objects of this memoir are to show, 



1st. That the marbles of Porto Venere, although possessing some 

 of the characters of transition rocks, may be the equivalents of part 

 of the oolitic series. 



2nd. That the diallage rock and serpentine of Southern Liguriahave 

 been protruded through the former at a period later than their formation. 



Previous to his description of the geological structure of the di- 



