marine biological station at port erin. 25 



Explanation op Plan and Sections. 



The Plan shows the disposition of deep and shallow 

 water in the wider northern part of the Irish Sea which 

 faces Lancashire. The contrast between the shallow area 

 to the east of the Isle of Man, and the deeper channel to 

 the west is obvious, and is also seen in the sections across 

 the region. 



In the sections the vertical scale is 88 times the 

 horizontal — ten fathoms in depth being equivalent to one 

 mile in distance. The land contour is not given. 



Section I. is taken along the line A — B, from Dundrum Bay in 

 Ireland, to Morecambe Bay in Lancashire, through Douglas 

 and Barrow. The depths are in fathoms. 



Section II. is taken due west from Southport along the line 

 C — D. The dotted line Do. indicates the longitude of 

 Douglas as the central point in Sections II., III., and in 

 Section II. the elevation marked 21 shows the southerly 

 extension of the plateau on which the Isle of Man lies. 



Section III. is taken along the line D — E, west-south-west, from 

 Southport to Wicklow through Anglesey and Holyhead 

 Island. It cuts through the deepest part of the channel 

 (over 80 fathoms), and shows the remarkable declivity on the 

 eastern side in going from Holyhead to Ireland. 



Section IV. runs along the line F — G, nearly north-west from 

 Liverpool through Port Erin in the Isle of Man, to 'Carlingford 

 Lough and Belfast. It shows the estuary of the Mersey and 

 the shallow waters of Liverpool Bay, important as shrimping 

 grounds aud flat fish " nurseries," while further out it passes 

 through the off shore fishing grounds and spawning areas at 

 over 20 fathoms. Between the Isle of Man and Ireland it cuts 

 through the deep channel at about 73 fathoms. 



Section V. runs north and south along the line H — J, from the 

 Mull of Galloway to Holyhead through Port Erin. It does 

 not cut the deep channel of over 50 fathoms in any part; 

 but lies almost wholly in these moderate depths of 20 to 40 

 fathoms which yield the most abundant and varied fauna to 

 the marine biologist. 



