SESSION 1906-1907. Ivii 



marine zoology. The Canon is one of our greatest authorities 

 on this subject, having spent the greater part of a long and active 

 life in the study of animal life in the sea. 



Before leaving, a vote of thanks was accorded to the President 

 on the proposition of Mr. Hopkinsou for his hospitality and the 

 very pleasant and instructive afternoon the members of the 

 Society had spent under his charge. 



Field Meeting, 15th June, 1907. 

 ALDBURY AND IVINGHOE. 



This was a joint meeting with the Greologists' Association, 

 held under the direction of Mr. Henry Kidner, F.Gr.S. Owing 

 to heavy rain in the morning it was but sparsely attended. 

 A waggonette was waiting for a party of nine at Tring Station, 

 and one member, the writer, joined later, cycling. 



Proceeding by way of Aldbury the steep road to the right was 

 ascended past a disused pit in the Middle Chalk (Terebrahdina 

 zone) and on to Aldbury Common, where Mr. Ashby's brickfield 

 was visited. This is an outlier of the Reading Beds which here 

 appear to have been much disturbed. Above them is brick-earth 

 for which the pit is chiefly worked. This is seen along the top of 

 the pit as a thick, irregular deposit of clay full of angular pieces 

 of flint with many pebbles of flint and a few of quartz. A hole 

 recently dug in one corner has resulted in the discovery of 

 a mass of clay 12 to 14 feet thick, brilliantly coloured in 

 various shades of purple, red, and green. Near the top 

 was an oval-shaped mass of fine, pale sand, suggestive of its 

 having been thrust into the clay while in a frozen condition. 

 Large flints were found in the lower part of the clay, and 

 extending through the mass in two places were irregularly- 

 contorted layers of flint-pebbles, having the appearance of 

 Tertiary pebble-beds squeezed by lateral pressure. Much sand 

 was seen amongst the clay. The Reading Beds appear to have 

 been disturbed by glacial action rather than deposited by ice. 



This is one of a series of five small Tertiary outliers which 

 run parallel with, the outcrop of the main mass on the northern 

 margin of the London Basin ; and the next one, at Ringshall, 

 was passed on the way to Ivinghoe Beacon. The summit of the 

 Beacon Hill, 762 feet above mean sea-level (about 50 feet lower 

 than the highest part of the ground which had been passed over 

 from Ringshall), is in the Upper Chalk, in the Holaster planus 

 zone, just above the Chalk Rock. The view over the G-ault plain 

 with the Lower Grreensand hills in the distance was interfered 

 with by heavy rain in gusts of wind, which ceased soon after 

 our descent. 



Near Ivinghoe a pit in the Lower Chalk was well worked for 

 fossils, and the zonal index-fossil, Holaster subglobosus, and 

 Terebratulina gracilis, were found ; also a " rag " bed full of 



