150 REV. THOMAS BROWN ON THE OLD RIVER TERRACES 



thickness, which ran for miles through the sections. Taking the order of 

 succession as it usually occurs, we find the following series : — Immediately 

 beneath the surface soil (sometimes 3 to 4 feet), there is the carse clay from 

 9 to 10^ feet in thickness, grey-coloured, tenacious, unlaminated, intermingled 

 with sand towards the base. Underlying this is a stratum of peat, the materials 

 of which seem to have been drifted from some distance, and one remarkable 

 thing is that the leaves, &c, which form this peat are found passing up into the 

 clay, plentifully intermixed with it at first, but getting less abundant as you 

 ascend. The clay and peat are in this way so associated that one might 

 almost view them as forming a single deposit. The portion of the series which 

 underlies the peat consists of laminated clay with partings of sand, and 

 laminated sands with partings of clay, going down under the surface of the 

 river. This lower series is unconformable to the overlying peat and clay, and 

 occasionally the former surface is seen to have been denuded, and the peat 

 and clay are found filling up the hollows. Some miles further up, near the 

 railway station at Forgandenny, the sandy layers are found to predominate, 

 with small gravel intermixed, and the whole has been consolidated into a 

 tolerably compact sandstone conglomerate, two yards of which are exj)osecl at 

 the base of the cliff underlying the peat. In regard to the peat itself and the 

 immediately overlying clay, it is found everywhere to contain wood, marsh 

 plants, such as the Arundo phragmites, hazel-nuts, mosses, &c. At one point 

 I found a series of leaves — willow, plane, &c. — in a singular state of pre- 

 servation, spread out between laminae of clay, displayed as in a herbarium, 

 and this continued layer after layer for a yard above the peat. The hazel- 

 nuts which occur in the peat are of a large size, and still show something of 

 the shining brown colour which belongs to them. There are occasional speci- 

 mens of beetles also, the elytra of which retain much of their brilliancy. My 

 examination of these deposits was by no means complete, but their general 

 character seemed sufficiently obvious. What was to be said in favour of 

 their marine or estuarine origin I really could not tell. No single trace of any 

 marine organism would turn up. For miles and miles the deposit was 

 laid open, but examine it where you might, all the remains were fresh- 

 water or land. The evidence was indeed to a great extent negative, and I 

 was not willing to come to any definite conclusion, but everything seemed 

 to indicate that these beds were merely a river formation. They rise about 

 27 feet above the present level of the stream. If only we could suppose a 

 time when the river floods had, like those of the Nile, the power of rising 

 27 feet, how natural and how easy the explanation of the whole phenomena 

 would be. 



Next autumn (1864) I went to Crieff, further up the Earn. Even on approach- 

 ing the town, looking through the windows of the railway carriage, I was struck 



