Reports & Proceedings — Geological Society of London. 285 



XVIII. — Another Fossil Tze-Tze Fly. 



FROM that extraordinarily rich deposit of Insecta at Florrisant, 

 comes another Tze-Tze fly, found in 1916, by Mr. George Wilson. 

 Mr. Cockerell, who describes it as Glossina vetema in the Manchester 

 Museum Publication No. 80, remarks that it is a "truly marvellous 

 specimen, showing not only the proboscis, wings, and bod}-, but even 

 the characteristic hairs ". The wings, which are quite clear, measure 

 10*9 mm. As there are now four species of Tze-Tze fly known from 

 Florrisant, Mr. Cockerell reminds us of Professor Osborn's suggestion 

 that a fly carrying disease-producing organisms may have been a 

 possible cause of the disappearance of the Tertiary herds which 

 formerly occupied America. 



DRIEIF'OIEITS .A-ZCsTID IFIROaiEIEIDIIISrGrS. 



I. — Geological Society op London. 



1. April 9, 1919.— Mr. G. W. Lamplugh, F.R.S., President, in the 



Chair. 



The following communication was read — 



"The Section at Worms Heath (Surrey), with Remarks on 

 Tertiary Pebble Beds and Clay-witb-Flints."' By William Whitaker, 

 B.A., F.R.S., F.G.S. (With "Penological Notes on the Beds at 

 Worms Heath", by George MacDonald Davies, M.Sc, F.G.S.) 



The chief pit now shows a fine set of more or less vertical pipes 

 in the Chalk, filled with pebbles and sands of the Blackheath Beds, 

 separated from the Chalk by Clay-with-Flints. 



The pebble beds here, like those elsewhere, consist of well-rolled 

 black flint pebbles, amongst which pebbles of a brownish quartzite 

 are occasionally found. It is concluded that the water in which 

 these flint pebbles were formed touched no other firm rock than 

 Chalk; but, as there are no subangular flints, the deposition of the 

 beds cannot have taken place close along a Chalk coast. 



The great mass of these pebbles is confined to the western part of 

 Kent and the adjoining part of Surrey, and they go but little way 

 underground beneath the London Clay northwards. A few patches 

 of pebbles at the same horizon have been mapped in the Hampshire 

 Basin, but heretofore have not been classed as Blackheath Beds. 



From a consideration of older Tertiary pebble beds, it seems that 

 these are not big enough to have afforded the material for the 

 Blackheath Beds. On the other hand, the Blackheath Beds may 

 have yielded the pebbles of the Bagshot Series in Essex, though not 

 in Hampshire. 



An examination of the various Tertiary pebble beds (up to the 

 Barton Series) points to overlaps of considerable extent; so much so 

 that the probable thinning of beds below the Barton Sand, in the 

 London Basin, and its former southward extension is comparable with 

 the underground thinning of the Wealden and Lower Cretaceous in 

 that area, though smaller and in a contrary direction. 



