xlviii PROCEEDINGS OF THE 



The Hagden Lane gravel-pita were next visited, and here the 

 irregular surface of the chalk under the gravel was well seen. In 

 continuation of his demonstrations of the geology of the neighbour- 

 hood, Mr. Whitaker stated that all gravels tended to form flats, 

 very nearly level, wherever, as here, there was a large extent of 

 gravel of any age. The gravels here were noteworthy as showing 

 no lines of bedding. The very uneven surface of the chalk seemed 

 to be due to its disintegration, by water, holding carbonic acid in 

 solution, percolating through the gravel above. The gravel where 

 not let down by this disintegration of the chalk was not more 

 than 20 feet in thickness, being comparatively insignificant in 

 section though occiipying large areas. 



Before leaving the pit a vote of thanks was accorded to Mr. 

 "VVhitaker, and on the way to Watford Station the members of the 

 Geologists' Association and a few members of the local Society had 

 tea at Wansford House, the residence of the Honorary Secretary. 



Field Meeting, 31st Mat, 1879. 



ElCKMANS'WORTH CoMMON MoOR. 



Eain was falling heavily, when, on the arrival of the half-past 

 two train from Watford, the members assembled at Eickmansworth 

 station, meeting there members of the Quekett Microscopical Club. 



After some time had been spent in waiting for the rain to partially 

 clear off, the station was left for the towing path at the side of the 

 canal, by which the Common Moor was reached. Nets, dipping 

 bottles, and other collecting appliances were then soon at work, 

 and a few interesting microscopic objects were obtained, but too 

 much rain had fallen on that and previous days, and the weather 

 was too cold and cloudy, for any of the rarer Rotifera or Polyzoa, 

 which are the most beautiful of the aquatic animals when viewed 

 under the microscope, to be secured. 



After several pools on the moor had been well tried with but 

 little success, the American water-weed {Anacharis alsinastnim) 

 growing in the running water was examined, and proved much 

 more prolific in minute animal life than the water in the stagnant 

 pools. Perhaps the most interesting object which was obtained in 

 abundance was the caddis, the larvaj of at least two species of 

 Fhrygania being collected. The dificrence between the case of a 

 species found in a running stream, and that of one found in com- 

 paratively still water, was remarked upon, the former being con- 

 structed chiefly of small stones or sand, and the latter of fragments 

 of wood, straw, and other light substances. 



When the collecting bottles were pretty well filled with objects 

 for future examination under the microscope, the members of the 

 two societies left the moor and returned to Watford by Cassio Bridge. 



