GEOLOGY 



II 



Apart from these elongated mounds the boulder clays and gravels are 

 mostly buried beneath late glacial and post-glacial clays and muds. York 

 owes its position to the morainic mounds which provided a feasible route 

 across the swampy vale at the tidal limit of the river Ouse. One swamp, 

 indeed, survives to the present day. Askham Bog, on the left of the road 

 and railway as one approaches the city from the Leeds direction, lies in a 

 hollow amongst the glacial ridges, from which there is no natural drainage 

 outlet. It is, in fact, the remnant of an inter- morainic lake.^ The flat 

 tract of Knavesmire, now the racecourse, occupies a somewhat similar 

 position ; in the early summer of 1932 it partially resumed the lake-like 

 condition. 



Since the immediate neighbourhood of York affords little opportunity 

 for studying the local geology in the field, it may be well to draw the 

 attention of visiting geologists to the chief features of interest in the 

 geological department of the museum and to certain points in what may 

 be called the ' human geology ' of the city. The museum and grounds of 

 the Yorkshire Philosophical Society will be open without charge to all 

 members of the British Association for the period of the meeting. In the 

 latter may be seen a few of the larger glacial boulders discovered in 

 the district and brought here for preservation. In the main building of the 

 museum the geological collections have been vastly improved under the 

 care of the present honorary curator, Mr. S. Melmore. One of the chief 

 treasures is the collection of mammalian remains from Kirkdale Cave, 

 rendered world-famous by Dr. Buckland. The specimens have recently 

 been cleaned and re-labelled, and are so arranged that all can be readily 

 inspected. The cave is, or rather was, situated about a mile and a half 

 west of Kirkby Moorside, but has been so largely removed by quarrying 

 as to be hardly worth a visit from the geological point of view. The 

 remains in the museum are probably the finest example of the contents of 

 an early Pleistocene hyena den in the world. In the same room will be 

 found an important collection of fossil bones from the pre-glacial beach 

 deposits of Sewerby, near Bridlington, and many mammalian fossils from 

 the drifts in various parts of the county. 



One room is devoted almost entirely to Saurian remains from the 

 Yorkshire Lias ; these include what is thought to be the largest nearly 

 complete Saurian known, a specimen of Ichthyosaurus crassimanus . In 

 the main geological gallery the attention of palasontologists will naturally 

 be drawn to the large number of type specimens, mostly Phillips's, which 

 have been brought together and well displayed by Mr. Melmore. Other 

 groups specially worthy of notice are the shells from the glacial beds of 

 Bridlington, etc., the specimens from the famous sponge-bed in the chalk 

 of Sewerby and Flamborough cliffs, and the plants from the Middle 

 Estuarine and Corallian rocks of North-East Yorkshire. 



In other departments of the museum are many exhibits which throw 

 interesting lights on the history of economic geology. In the Hospitium, 

 which houses most of the Roman antiquities, the lead cofEns and water- 

 pipes show the lavish use of that metal by the Romans. There is no 



* Reference to the botany of this bog will be found in Chap. IV, and to its 

 zoology in Chap. V. 



