762 DK R. KIDSTON AND PROF. W. H. LANG ON OLD RED SANDSTONE PLANTS 



plete exposures were laid bare which showed that the chert bed was interbedded 

 with the Dryden Shales and therefore referable to the Old Red Sandstone.* 



From the section exposed in trench No. 1 t in the lower field between Easaiche 

 Bridge and Windyfield farmhouse the following measured section was taken : — 



Section of Chert Band in Trench No. 1, in First Field North of Easaiche 

 Bridge, on South-east Side of Path and Ditch separating two Fields, and 

 178 Feet North-east of the Road, Muir of Rhynie, Aberdeenshire. 



\° 



N 



ft. in. 

 5 



6 



M 



K 



H 



G 



9 



1 



3 



3 



E 



1 



3 



5 



1 1 



22 

 21 



20 | 



19 



18a 



186 



17 



16 



15 



U 



13 



12 



11 

 111 



°{ 



10 



Dryden Shales. 



Bedded silicious sandstone in very thin layers with carbonaceous remains. 



Silicious sandstone with sandy layer and lenticular masses of silicified peat formed 



of Rhynia, 

 Silicious sandstone with irregular beds of chert full of Rhynia. Sandstone formed 



of very thin layers separated by black lines, irregularly bedded, and full of 



carbonised plant-remains. 



Silicified peat mixed with sandy matter. Vegetable remains much broken up. 



Layer of silicious sandstone at top and at base, the latter about 1 inch thick. 

 Intermediate portion formed of silicified peat composed of Rhynia. Vegetable 

 remains in lower part of bed much broken up. Upper part contains stems little 

 or not compressed. 



Bedded silicified peat composed of 

 occasionally some sandy material. 



Bed of silicious sandstone with intercalated 

 Rliynia. 



Rhynia, in part much decomposed, with 

 lenticular patches of peat formed of 



Silicified peat with much broken-up vegetable remains. Thin sandy layer at top. 



Bed of silicified peat with thin-bedded sdicious sandstone at top about ^ inch thick. 

 Rhynia slightly compressed. 



Much decomposed bed of silicified peat composed of Rhynia. 



Bed of silicified peat formed of Rhynia, a good deal decomposed and broken up, 

 with thin layer of very fine-bedded silicious sandstone at top and base. 



Irregular thin beds of silicious sandstone. Silicified peat formed of broken-up and 

 decomposed Rhynia. 



Bedded silicified peat formed of Rliynia with layer of fine bedded silicious sand- 

 stone, about \ inch thick at top, with another of about the same thickness at base. 



Silicious bed of sandstone in very thin laminae at top, less than 1 inch thick, with 

 black lines on bedding surfaces. Remainder of bed composed of more or less 

 distinctly bedded silicified peat formed of Rhynia. The stems in this, as in 

 most of the other beds, lie horizontal with the bedding and in many cases are 

 almost uncompressed, while at other places in this bed the vegetable matter is 

 much decomposed and broken up. At one place a sandy layer occurs which has 

 followed the natural irregularities of the surface of the peat at the time of 

 deposition (see PI. I, fig. 1), a feature characteristic of the sand beds which 

 occur in the silicified peat. 



* The exact horizon of the Rhynie Old Red Sandstone has not yet been definitely determined, but it cannot be 

 younger than the Middle Old Red Sandstone. 



f The site of this trench is shown on the map (fig. 1) in the Report of the Committee on "The Plant-bearing 

 Cherts at Rhynie, Aberdeenshire," Brit. Assoc. Rep., 1916, Newcastle Meeting. 



