in Scotland and Parts of England. 273 



Mytilus umbilicatus, Littorina littorea, Buccinum undatum, 

 Natica clausa, Balanus sulcatus, suggesting an arctic cha- 

 racter in the sea of the period. Remains of large quadrupeds 

 have also been found in this set of deposits. In the deep 

 beds wrought for bricks at Portobello, large trees are reported 

 as having been found by^the workmen, and thought by them 

 to be of oak ; as also, bones " as thick as a man's thigh." 

 They are likewise understood to have found hazel nuts lying 

 on the surface of the deposit. 



This evidently aqueous formation of a tranquil era, during 

 which there had been dry land inhabited by the elephant, 

 rhinoceros, stag, and other large mammalia, is succeeded by 

 what Mr Milne Home calls the coarse gravel or stony clay, 

 but what is more generally recognised in Scotland as the 

 till, being the subsoil of many of our fields (No. 3). This 

 formation may be described as a layer of rough stones, em- 

 bedded in a light -coloured clay, not so thick as the boulder 

 clay generally is, while the included blocks are also of smaller 

 size. It has no laminae, no organic remains, and has all the 

 appearance of having been the product of violent agencies. 

 It appears to be often confounded with the boulder clay, and 

 thus has given rise to some serious mistakes regarding the 

 arrangement of the superficial deposits. It is often, how- 

 ever, placed immediately over the surface of the rocks. 



Over this again comes a new series of sand-beds (No. 4), 

 containing thin layers of gravel, and fragments of coal, — a very 

 wide-spread formation in our immediate neighbourhood, and 

 throughout Scotland generally. Mr Milne Home found it at 

 Blackshiels, 700 feet above the sea, and it probably exists at 

 greater elevations. This very careful observer had not heard 

 of any shells being ever found in it. 



The same gentleman has described a raised beach which 

 extends along the Firth of Forth, (No. 5,) rising from fifteen 

 feet in the east, to about thirty in the west, above the level 

 of the sea, in which he found beds of shells of existing 

 species ; and this appears, from his description, to be an in- 

 tercalated formation, though probably represented by some 

 of the shell-bearing beds found by Mr Smith of Jordanhill, 

 and Mr John Craig, in the basin of the Clyde. The bed is 



