Fortune : Turtle Dove Nesting near Scarborough. 



273 



the A. contorta zone in the district is a strongs arg-ument in 

 favour of the negative side of the question. 



iVfter the unsuccessful quest of the Rhaetics, attention was 

 turned to the old Liassic floor on which the Red Chalk rests. 

 A very fair exposure of the Chalk with pink bands was seen at 

 Great Givendale, and when White Keld Spring-s were reached, 

 a very interesting section of Red Chalk with ferruginous sand 

 resting on some doubtful shales. These were carefully examined 

 for organic remains, but proved barren, though their aspect was 

 that of the Lias. At Millington Springs we had the Red Chalk 

 with its characteristic Belemnite again and below it a blue clay 

 appeared. This could be referred with some confidence to the 

 Lower Lias, though no direct evidence was obtained. A little 

 lower down the dale the top of the Red Chalk with the Grey 

 above was seen, and from the two exposures it would seem 

 that the Red Chalk could not have exceeded 5 feet in thickness. 

 These sections, together with that of Saturday, complete the 

 evidence obtained for the striking unconformity already referred 

 to. Owing to the absence of fossils it was not possible to 

 determine the particular zones of the Lias seen on Monday, and, 

 consequently it was not possible to throw much new light on 

 the structure of the Market Weighton anticline. It might be 

 pointed out, however, that the statement in the circular that 

 ' the disturbance was initiated in the interval between the 

 deposition of the Middle Coal Measures and that of the 

 Permian' does not go far enough, and hardly does justice 

 to this striking example of the effect of persistent earth move- 

 ments. The paucity of sections renders a discussion rather 

 difficult, but sufficient is known to make it clear now, as a 

 result of recent deep borings, that a differential earth movement 

 in a vertical plane was in operation during the deposition of 

 the Middle Coal Measures, and continued intermittently up to 

 the deposition of the Chalk. How much further back than 

 Middle Coal Measure time the initiation of the axis should be 

 placed is impossible to say in the present state of knowledge. 

 That the ridges and hollows of the old Silurian floor played 

 an important part in shaping the present boundaries of the coal 

 basins is becoming, however, more and more evident as their 

 structure is being studied. 



Turtle Dove Nesting near Scarborough. — A pair of these 

 beautiful birds nested at Wykeham in June. — R. Fortune, 

 Harrogate. 



1905 September i. • S ' 



