president's address. 517 



These explanations, accompanied by comments and observations 

 from Mr. Howse and others, rendered this part of the day's pro- 

 ceedings highly interesting and instructive ; especially as to the 

 Geology of this part of Northumberland, and contemporaneous 

 strata in other districts. It is to be regretted, however, that the 

 upper strata of Mr. Mundle's section cannot at present be directly 

 connected with the lower ones of Westgarth Forster's section, of 

 the Coal and Mountain Limestone formation. The break occurs 

 between the whin sill and the top of this section, and cannot be 

 very considerable. It is to be hoped, that at no distant period, 

 the intermediate strata may be ascertained, and a complete sec- 

 tion of the Northumberland strata, from the New Red, down to 

 the Old Red Sandstone, obtained. One very puzzling fact in 

 the identification of the strata, is the way in which the several 

 beds of limestone (which in the Midland Counties form one thick 

 stratum) become split up and divided as they approach the north ; 

 and are therefore more difficult to recognise and identify, although 

 fossils peculiar to, and characteristic of, some of the seams, are 

 beginning to be recognised. These, however, before being re- 

 ceived and accepted as infallible means of identification, must be 

 rigidly tested by observation, and then the value of characteristic 

 fossils is great indeed. It is to be hoped that Saccammina Carteri, 

 discovered by Sir Walter Trevelyan near Wallington, and since 

 found rather abundantly in the four-fathom limestone (but in no 

 other bed), may prove to be so, of that bed of the Limestone, 

 as, though insignificant in size, it is conspicuous in appearance.* 



Mr. Howse mentioned, in connexion with the section of strata 

 shown to us to-day, that in a depth of about a hundred fathoms, 

 there are ten alternations of marine and fresh-water deposits. 



The mining operations now going on, consist in the separation 

 of ironstone nodules of excellent quality, from a bed of blue shale 

 or clay, about thirty feet thick, in which they are scattered, 

 something like plums and currants in a cake ; in consequence 

 of the shale bed lying generally at the surface of the ground, 

 and parallel to it, it is often cut through from top to bottom in 



* Since the above was in print, Mi-. Howse tells me he has found Saceammina Carteri, in 

 the Great Limestone, neai' Bollisllope ( on Alston Mooi\ 



