Mr. Georjre Tate on the Fame Islands. 233 



o 



found in several localities in Northumberland, but never pre- 

 viously a complete specimen. It belongs to the genus Griffi/hides 

 of Portlock ; but as it differs from any recorded species, I have 

 described and named it, after the locality, Griffit/tides Farnensis, 



From the stratified beds of Fame and Fosseland, I have deter- 

 mined twenty-eight species of organisms, the greater proportion 

 of which are Brachiopods ; they correspond generally with those 

 found at North Sunderland, and more especially at Howick, and 

 they indicate the Fame strata to be of equivalent age, and to 

 belong to one of the lower groups of the Mountain Limestone 

 formation. 



On these islands are patches of the Boulder formation, which 

 covers over many parts of Northumberland ; it forms the subsoil 

 of the Fame, and on the Stapel this same clay is 3 feet thick, 

 overlying the basalt. 



The basalt of these islands is not a dyke passing vertically 

 through the strata, but a portion of the overlying or interstrati- 

 fied igneous rocks, which, commencing at Kyloe, and passing by 

 Belford, Barabro, Craster, Howick, Ratcheugh, Alnwick, and 

 Shieldykes, extend south-westward through the county, and 

 which, appearing like a stratum among sedimentary rocks, are 

 frequently called the Whin-sill. Regarding their origin and intro- 

 duction among the strata, different opinions have been advanced ; 

 Professor Sedgwick maintaining that the basaltic lava was 

 erupted subsequently to the deposition of the carboniferous beds, 

 and forced among them along their surfaces of stratification; 

 while Mr. Hutton is of opinion that the basalt was erupted at one 

 or several different periods during the deposition of the carboni- 

 ferous rocks, so as to be covered up by portions of them, and to 

 be thus interstratified with them. With the limited number of 

 facts presented by the Fame, it would be out of place to discuss 

 the general question here ; but it may be conclusively inferred 

 from these facts, that the basalt of the Fame was erupted subse- 

 quently to the deposition of the sandstone, limestone, and shale 

 beds on Fosseland, for that eruption has obviously been the 

 cause of the isolated, metamorphic and disturbed condition of 

 these beds. 



LIST OF FOSSILS. 



BRYOZOA. 



Fenestella plebeia, M*Coy. In red shale and chert, Fosseland. 



undulata, Phil. Fosseland. 



' crassa, AVCoy. Fosseland. 



Sulcoretepora parallela, Phil. Fosseland. 



B.N.C. — VOL. III. N**. VII. T 



