Yorkshire Naturalists at Pocklington. 271 



Mention should also be made of the gravels in the neig-h- 

 bourhood of Broug-h and Elloug-hton, the remarkable deposit of 

 big" ang-ular boulders of local rocks at Sancton, and the fossil- 

 iferous marls at Bielsbeck. 



From the foreg'oing- facts it is manifest that the superficial 

 deposits of this part of the Plain of York offer a very interesting- 

 field to geologfists investigfating- the glacial and post-g-lacial 

 problems of our county. 



As reg-ards the origin of the chalky gravel more particularly 

 under the observation of the geologists at Pocklington, the 

 opinion was expressed that the forces now in operation were 

 insufficient to account for the spread of this material over such 

 a wide area, but that probably the gravel was formed originally 

 in the bottoms of the adjacent big dales of Millington, Deep 

 Dale, and Warter Dale, to be subsequently swept out into the 

 plain by water rushing- down the valleys from the higher levels. 



For the 'Solid' Geology Mr. Cosmo Johns, F.G.S., writes : — 

 Having regard to the many points of geological interest in 

 a district like that of Pocklington it was to be regretted that 

 time did not permit of a more extended investigation. Under 

 the circumstances attention, so far as the solid rocks were 

 concerned, w^as concentrated on the remarkable unconformity 

 between the Chalk and Lias, and also in endeavouring to 

 trace the supposed Rhaetic beds that have been mapped there. 

 Incidentally the party came across a most interesting example 

 of a fault in the Keuper Marls in the White Brick and Tile 

 Works. The varied colours of the marls contrasted well and 

 made the fault appear very striking. To return, however, to 

 the evidence of the Market Weighton unconformity. The most 

 interesting section was undoubtedly that seen on Saturday. In 

 the beck below Warter Priory the Ammonites plaiiorhis zone of 

 the Lias was seen and Pleuromya crowcombeia obtained. The 

 Ammonites angulatus zone was not visible, but in the upper part 

 of the park near the brickyard the A. biicklandi zone appeared, 

 and just above could be seen the Red Chalk. This was satis- 

 factory in that an idea could be formed as to the extent of 

 the pre-Cretaceous denudation. Coming from Warter it was 

 interesting to note when crossing the Kildwick Percy hill that 

 the Red Chalk appeared on both sides, wrth the Grey Chalk and 

 Chalk with flints above. On Monday a careful search was made 

 up the beck at Swinebridge for the supposed Rhaetic beds 

 mapped there. A fair section of the Keuper Marls was noted, 

 but nothing that could with certainty be referred to the Rhaitics 



1905 September i. 



