XXll PROCEEDINGS OF THE 



2. " Meteorological Observations taken at Holly T^ank, "Watford, 

 during the half-year ending 31st August, 1877." By John 

 Hopkinson, F.L.S., F.M.S., etc., Hon. Sec. [Vide p. 91.) 



3. ''Heport on the Rainfall in Hertfordshire in 1877." By the 

 Honorary Secretary. {Vide p. 97.) 



4. "Keport on Phenological Observations in Hertfordshire in 

 1877." By the Honorary Secretary. ( F/f/e p. 101.) 



5. "Notes for Observations of Injurious Insects." By Eleanor 

 A. Ormerod, F.M.S. Communicated by the Honorary Secretaiy. 

 {Vide^. 11.) 



6. "Notes on Economic Entomology." By Eleanor A. Ormerod. 

 Communicated by the Honorary Secretary. ( Vide p. 84.) 



Field Meeting, 18th May, 1878. 

 Tyler's Hill, Chesham. 



At various places beyond the northern limit of the London 

 Tertiary Basin outliers of the Lower Eocenes occur, ranging on the 

 whole in a line parallel with the margin of the main mass of which 

 they at one time formed a part. One of these, separated from the 

 main mass by a greater distance than is usually the case, is at 

 Tyler's Hill, or Cowcroft, as it is sometimes called, a mile and a 

 half to the east of Chesham. The nearest railway station is at 

 Boxmoor, and here, at about a quarter to three, a party consisting 

 of members of the Society and of the Geologists' Association 

 of London, assembled for the purpose of visiting this outlier under 

 the guidance of Mr. John Evans, D.C.L., F.R.S. 



The distance being five miles each way, a wagonette was engaged 

 which the ladies of the party availed themselves of. An ascent by 

 Box Lane had first to be made, and for about a quarter of a mile 

 up the hill the Chalk was seen to come to the surface, sections 

 being exposed in several small pits, and in the road-side banks, 

 owing to the road being excavated to reduce its steepness. 



On the higher ground the Chalk is covered for a considerable 

 distance with " brick-earth " and " elay-with-flints." This elevated 

 plateau, some 500 feet above sea-level, suddenly ends at Layhill 

 Common, which is approached by a steep descent to the Chalk, 

 here exposed by the erosion of a stream, no longer in existence, 

 which at one time must have joined the Chess near Flaunden. 

 From Layhill Common, where the Chalk is covered by glacial 

 gravel, there is a gentler rise of the ground towards the outlier, 

 which is conspicuous for some distance by the dense wood which 

 covers it. The presence of this wood seems to be entirely due to 

 the existence of the outlier of which Tyler's Hill is formed ; and 

 to this outlier the protection of the hill itself fx'om denudation is, 

 no doubt, also due. A chalk-pit and brickfields expose a complete 

 section of the hill from the London Clay down to the Chalk. 



The following description of this section is given by Professor 



