6 SCIENTIFIC SURVEY OF YORK AND DISTRICT 



near the marginal uplands to barely 25 inches in the centre of the region. 

 The wettest month is October, and the late summer receives a noteworthy 

 share of rain, but September is comparatively dry. The fact that July 

 and August are credited with few rainy days in relation to the amount of 

 rain which they receive, so that rain is most intense at this time, is due to 

 a high frequency of thunderstorms. September favours the harvest, but 

 the heavy falls of late summer frequently deplete the yield of various 

 crops. (CHmatic details for York will be found in Chap. III.) 



The city of York stands where the Ouse, changing direction from 

 south-east to south , breaks through the more northerly of the two morainic 

 ridges already noted, and at a point where the river is joined by a left-bank 

 tributary, the Foss. The latter, meandering south, enters the Ouse at 

 a sharp angle just within, i.e. north of, the ridge. The moraine, on 

 reaching the Ouse from the east, loses its identity as a ridge and widens 

 north and south along both banks of the river into a complicated series of 

 elongated mounds. Thus boulder clay is heaped upstream as far as the 

 bend at Clifton ; sands and gravels sprawl downstream to Bishopthorpe 

 and Fulford, and, indeed, struggle as far as the southern moraine at 

 Escrick. A little west of the Ouse the moraine regains individuality, but 

 rather as a series of minor ridges than as a single major feature. As a 

 result of these complications the land rises most steeply from, and 

 achieves its maximum elevation along, the banks of the Ouse immediately 

 above the point where the Foss enters it ; it is flanked there by boulder 

 clay. This applies especially to the left bank or north side, as it may be 

 called just here. It was on this side, on the low eminence in the angle of 

 the confluence, overlooking the Ouse and the marshy terrain spreading 

 along and beyond the Foss, with forest and more marsh on the third side, 

 that the Roman fortress was built ; and this area has persisted as the core 

 of the city from its genesis. Placed at once both in the geographical 

 centre of the vale and at the crossways of its arterial natural routes, the 

 north-south route by the river and east- west route via the moraine, the 

 settlement also clearly enjoyed a good command over the surrounding 

 low- lying lands and a large measure of natural security. 



Despite the march of time, the salient features of the lay-out of Roman 

 York can still be recognised. Stonegate adheres fairly faithfully to the 

 line of the Via Principalis, High and Low Petergate to that of the Via 

 Praetoria, while Blossom Street, Bootham, Monkgate and Walmgate 

 represent the original approach roads to the gates of the castra. The 

 suburban, i.e. extra-mural, development which marked later Roman times 

 was identified mainly with the high ground on the south side of the Ouse 

 and chiefly the neighbourhood where the railway station now stands. 

 Subsequent expansion followed very much in the Roman wake and 

 resulted in further walls being erected. Those built under the Normans 

 were closely related to the walls which followed later in the mediaeval 

 age, and are preserved to-day. On the north-east and north-west the 

 latter conform almost exactly in alignment to the Roman walls, while to 

 the south-west they enclose roughly the area of Roman suburban settle- 

 ment. On the south-east there is an extension from Feasegate to Paragon 

 Street. The absence of walls in the vicinity of the Foss is sufficient 



