258 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 16, 



Kincardine, since the base in South. Perthshire is composed of a con- 

 glomeratic mass fully equal in thickness to the lower conglomerates 

 of the country south and east of the Moray Pirth. In Forfar and 

 Kincardine the lowest members are composed of Forfarshire flags and 

 inferior red shaly sandstones ; but in the district under consideration 

 we have, underneath the representatives of the Forfarshire flags and 

 beds equivalent to the inferior red shaly sandstones, a thick con- 

 glomeratic series, differing in the nature of its fragments from the 

 higher conglomerates ; and this, both in position and thickness, can 

 only be parallel with the base of the Old Eed, as occurring in the 

 countries which margin the Moray Firth. 



Organic remains. — Eeference has already been made to the dis- 

 covery of Pteraspis by Mr. Powrie in the grey beds at Westertown 

 Quarry, near the Bridge of AUan. This form, I learn from Prof. 

 Huxley, is probably P. rostratus. I have also stated that Mr. Bryson 

 has procured from the same locality a specimen of Cephalaspis, This 

 specimen has unfortunately been mislaid. From this spot I have 

 likewise obtained, along with remains of Pteraspis, the head of a 

 Cephalaspis. This specimen is not in a very perfect condition, and 

 the species cannot be satisfactorily made out by Prof. Huxley ; it is 

 therefore desirable that the fossils from the Bridge of Allan should 

 be carefuUy looked after in order that the form of Cephalaspis which 

 is associated with Pteraspis here may be determined. 



No traces of Plants, so far as I am aware, have been found in this 

 neighbourhood, nor are there any remains of Crustaceans. 



With reference to the strata which overlie the grey sandstones 

 reposing on the inferior conglomerates, I have seen it stated that the 

 brown sandstones of Doune afford Cephalaspis Lyellii ; but this is 

 a matter on which I am in doubt, as I can get no satisfactory evi- 

 dence of the occurrence of this fish in this portion of the Old Red 

 Sandstone area of Scotland. 



2. On the Western End of the London Basin ; on the Westerly 

 Thinning of the Lower Eocene Beds in that Basin ; and on the 

 Greywethees of Wiltshire. By William Whitaker, B.A. 

 (Lond.), F.G.S., of the Geological Survey of Great Britain. 



Contents. 

 Introduction. 

 I. Tertiary Outhers in the N.E. part of Sheet 14 of the Map of the Geological 

 Survey of Great Britain. 

 Surface-deposits on the top of the Chalk-hills in the above district. 



II. Thanet Sand. 



Woolwich and Eeading Beds. 

 I Basement-bed of the London Clay. 

 \ London Clay. 



Effect of the Westerly Thinning of the Lower Eocene Beds. 



III. Grey wethers. 



The Sands of Netley and Headley Heaths (Surrey). 



Introduction. — The above three subjects are closely akin to one 

 another. The sections that will be described in the first part of this 



