Geological Society. 307 



teeth of the Basilosaurus with those of the Dugong and other ani- 

 mals, admits the correctness of the inferences of its mammiferous 

 nature, proposes to substitute for the name of Basilosaurus that of 

 Zeuglodon, suggested by the form of the posterior molars, which re- 

 semble two teeth tied or yoked together. 



A notice on " the Occurrence of Graptolites in the Slate of Gal- 

 loway in Scotland," by C. Lj'ell, Esq., V.P.G.S., was first read. 



On examining some specimens of slaty sandstone and shale, col- 

 lected by Mr. John Carrick Moore, on the shore of Loch Ryan in 

 Galloway, Mr. Lyell discovered distinct remains of Graptolites, re- 

 sembling those found in the Silurian strata of England and Sweden. 

 As Mr. Lyell is not aware of these zoophytes having been before 

 observed in Scotland, and as organic remains are exceedingly rare 

 in the great range of slaty sandstone and shale which extends from 

 St. Abb's Head to Galloway, he considers the discovery of a fossil, 

 affording a test of the relative age of those beds, not unimportant. 

 The strata containing the Graptolites are nearly vertical, and their 

 strike is west-south-west and east-north-east. 



Mr. Sharpe's paper " On the Geology of the Neighbourhood of 

 Lisbon," commenced at the meeting held on the 9th of January, was 

 then concluded. 



In 1832, Mr. Sharpe laid before the Society, a short account of 

 the geological structure of the neighbourhood of Lisbon * ; but having 

 since that period resided for a considerable time in the same district, 

 he gave in the paper read on the 23rd instant, the result of his more 

 extended and matured acquaintance with the country. 



The tract described by Mr. Sharpe, is bounded towards the north 

 by a line extending from Torres Vedras by Sobral to Villa Franca, 

 and in the south by the coast from Cape Espichel to St. Ubes; and 

 the whole of its area is about 650 square miles. 



The formations are arranged by the author in the following order, 

 the local names having been taken from the points where the strata 

 are best exhibited : 

 Tertiary, (a.) Upper tertiary sand. — (b.) Almada beds. — (c.) Lower 



tertiary conglomerate. 

 Secondary, (d.) Hippurite limestone. — (e.) Red sandstone. — (y.) 

 Espichel limestone. — {g.) Slate clay and shale. — (A.) San 

 Pedro limestone. — (i.) Older red conglomerate. 

 Igneous Rocks. — Basalt. — Granite. 



TERTIARY FORMATIONS. 



The tertiary deposits occupy a tract, only a portion of which is 

 included within Mr. Sharpe's district, as they extend in a north-east 

 direction toAbrantes, a distance of eighty miles, and in a south-east to 

 Alcacer do Sal, a distance of fifty miles. The Tagus flows through 

 the tract from Abrantes to the sea, but the greater part of the ter- 

 tiary strata are situated to the south of the river. 



(«.) Upper Tertiary Sand. — This formation consists of about 100 

 feet of fine gray quartzose sand, and 150 feet of coarse quartzose 

 ferruginous sand and gravel. It constitutes nearly the whole of the 

 ♦ Proceedings, vol. i. p. 394. [or L. & E. Phil. Mag., vol. i. p. 227. — Ed,] 



X2 



